def __call__(self, x, coerce=True, hold=False, prec=None,
dont_call_method_on_arg=False):
"""
Note that the ``prec`` argument is deprecated. The precision for
the result is deduced from the precision of the input. Convert
the input to a higher precision explicitly if a result with higher
precision is desired.::
sage: t = exp(RealField(100)(2)); t
7.3890560989306502272304274606
sage: t.prec()
100
TESTS::
sage: exp(2,prec=100)
doctest:...: DeprecationWarning: The prec keyword argument is deprecated. Explicitly set the precision of the input, for example exp(RealField(300)(1)), or use the prec argument to .n() for exact inputs, e.g., exp(1).n(300), instead.
7.3890560989306502272304274606
"""
if prec is not None:
from sage.misc.misc import deprecation
deprecation("The prec keyword argument is deprecated. Explicitly set the precision of the input, for example exp(RealField(300)(1)), or use the prec argument to .n() for exact inputs, e.g., exp(1).n(300), instead.")
x = GinacFunction.__call__(self, x, coerce=coerce, hold=hold,
dont_call_method_on_arg=dont_call_method_on_arg)
return x.n(prec)
return GinacFunction.__call__(self, x, coerce=coerce, hold=hold,
dont_call_method_on_arg=dont_call_method_on_arg)
def __init__(self):
r"""
Derivatives of the Riemann zeta function.
EXAMPLES::
sage: zetaderiv(1, x)
zetaderiv(1, x)
sage: zetaderiv(1, x).diff(x)
zetaderiv(2, x)
sage: var('n')
n
sage: zetaderiv(n,x)
zetaderiv(n, x)
sage: zetaderiv(1, 4).n()
-0.0689112658961254
sage: import mpmath; mpmath.diff(lambda x: mpmath.zeta(x), 4)
mpf('-0.068911265896125382')
TESTS::
sage: latex(zetaderiv(2,x))
\zeta^\prime\left(2, x\right)
sage: a = loads(dumps(zetaderiv(2,x)))
sage: a.operator() == zetaderiv
True
"""
GinacFunction.__init__(self, "zetaderiv", nargs=2)
def __init__(self):
r"""
The hyperbolic cosine function.
EXAMPLES::
sage: cosh(pi)
cosh(pi)
sage: cosh(3.1415)
11.5908832931176
sage: float(cosh(pi))
11.591953275521519
sage: RR(cosh(1/2))
1.12762596520638
sage: latex(cosh(x))
\cosh\left(x\right)
sage: cosh(x)._sympy_()
cosh(x)
To prevent automatic evaluation, use the ``hold`` parameter::
sage: cosh(arcsinh(x),hold=True)
cosh(arcsinh(x))
To then evaluate again, use the ``unhold`` method::
sage: cosh(arcsinh(x),hold=True).unhold()
sqrt(x^2 + 1)
"""
GinacFunction.__init__(self, "cosh", latex_name=r"\cosh")
def __init__(self):
r"""
The hyperbolic sine function.
EXAMPLES::
sage: sinh(pi)
sinh(pi)
sage: sinh(3.1415)
11.5476653707437
sage: float(sinh(pi))
11.54873935725774...
sage: RR(sinh(pi))
11.5487393572577
sage: latex(sinh(x))
\sinh\left(x\right)
sage: sinh(x)._sympy_()
sinh(x)
To prevent automatic evaluation, use the ``hold`` parameter::
sage: sinh(arccosh(x),hold=True)
sinh(arccosh(x))
To then evaluate again, use the ``unhold`` method::
sage: sinh(arccosh(x),hold=True).unhold()
sqrt(x + 1)*sqrt(x - 1)
"""
GinacFunction.__init__(self, "sinh", latex_name=r"\sinh")
def __init__(self):
r"""
The hyperbolic cotangent function.
EXAMPLES::
sage: coth(pi)
coth(pi)
sage: coth(0)
Infinity
sage: coth(pi*I)
Infinity
sage: coth(pi*I/2)
0
sage: coth(7*pi*I/2)
0
sage: coth(8*pi*I/2)
Infinity
sage: coth(7.*pi*I/2)
-I*cot(3.50000000000000*pi)
sage: coth(3.1415)
1.00374256795520
sage: float(coth(pi))
1.0037418731973213
sage: RR(coth(pi))
1.00374187319732
sage: bool(diff(coth(x), x) == diff(1/tanh(x), x))
True
sage: diff(coth(x), x)
-1/sinh(x)^2
sage: latex(coth(x))
\operatorname{coth}\left(x\right)
"""
GinacFunction.__init__(self, "coth", latex_name=r"\operatorname{coth}")
def __init__(self):
r"""
The absolute value function.
EXAMPLES::
sage: var('x y')
(x, y)
sage: abs(x)
abs(x)
sage: abs(x^2 + y^2)
abs(x^2 + y^2)
sage: abs(-2)
2
sage: sqrt(x^2)
sqrt(x^2)
sage: abs(sqrt(x))
abs(sqrt(x))
sage: complex(abs(3*I))
(3+0j)
sage: f = sage.functions.other.Function_abs()
sage: latex(f)
\mathrm{abs}
sage: latex(abs(x))
{\left| x \right|}
"""
GinacFunction.__init__(self, "abs", latex_name=r"\mathrm{abs}")
def __init__(self):
r"""
The hyperbolic cosecant function.
EXAMPLES::
sage: csch(pi)
csch(pi)
sage: csch(3.1415)
0.0865975907592133
sage: float(csch(pi))
0.0865895375300469...
sage: RR(csch(pi))
0.0865895375300470
sage: csch(0)
Infinity
sage: csch(pi*I)
Infinity
sage: csch(pi*I/2)
-I
sage: csch(7*pi*I/2)
I
sage: csch(7.*pi*I/2)
-I*csc(3.50000000000000*pi)
sage: bool(diff(csch(x), x) == diff(1/sinh(x), x))
True
sage: diff(csch(x), x)
-coth(x)*csch(x)
sage: latex(csch(x))
{\rm csch}\left(x\right)
"""
GinacFunction.__init__(self, "csch", latex_name=r"{\rm csch}")
def __init__(self):
r"""
The hyperbolic secant function.
EXAMPLES::
sage: sech(pi)
sech(pi)
sage: sech(3.1415)
0.0862747018248192
sage: float(sech(pi))
0.0862667383340544...
sage: RR(sech(pi))
0.0862667383340544
sage: sech(0)
1
sage: sech(pi*I)
-1
sage: sech(pi*I/2)
Infinity
sage: sech(7*pi*I/2)
Infinity
sage: sech(8*pi*I/2)
1
sage: sech(8.*pi*I/2)
sec(4.00000000000000*pi)
sage: bool(diff(sech(x), x) == diff(1/cosh(x), x))
True
sage: diff(sech(x), x)
-sech(x)*tanh(x)
sage: latex(sech(x))
\operatorname{sech}\left(x\right)
"""
GinacFunction.__init__(self, "sech", latex_name=r"\operatorname{sech}",)
def __init__(self):
r"""
The inverse of the hyperbolic cosecant function.
EXAMPLES::
sage: arccsch(2.0)
0.481211825059603
sage: arccsch(2)
arccsch(2)
sage: arccsch(1 + I*1.0)
0.530637530952518 - 0.452278447151191*I
sage: arccsch(1).n(200)
0.88137358701954302523260932497979230902816032826163541075330
sage: float(arccsch(1))
0.881373587019543
sage: diff(acsch(x), x)
-1/(sqrt(x^2 + 1)*x)
sage: latex(arccsch(x))
\operatorname{arccsch}\left(x\right)
"""
GinacFunction.__init__(self, "arccsch",
latex_name=r"\operatorname{arccsch}",
conversions=dict(maxima='acsch'))
def __init__(self):
r"""
The inverse of the hyperbolic secant function.
EXAMPLES::
sage: arcsech(0.5)
1.31695789692482
sage: arcsech(1/2)
arcsech(1/2)
sage: arcsech(1 + I*1.0)
0.530637530952518 - 1.11851787964371*I
sage: arcsech(1/2).n(200)
1.3169578969248167086250463473079684440269819714675164797685
sage: float(arcsech(1/2))
1.3169578969248168
sage: diff(asech(x), x)
-1/(sqrt(-x^2 + 1)*x)
sage: latex(arcsech(x))
\operatorname{arcsech}\left(x\right)
"""
GinacFunction.__init__(self, "arcsech",
latex_name=r"\operatorname{arcsech}",
conversions=dict(maxima='asech'))
def __init__(self):
r"""
The hyperbolic sine function.
EXAMPLES::
sage: sinh(pi)
sinh(pi)
sage: sinh(3.1415)
11.5476653707437
sage: float(sinh(pi))
11.54873935725774...
sage: RR(sinh(pi))
11.5487393572577
sage: latex(sinh(x))
\sinh\left(x\right)
To prevent automatic evaluation, use the ``hold`` parameter::
sage: sinh(arccosh(x),hold=True)
sinh(arccosh(x))
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: sinh(arccosh(x),hold=True).simplify()
sqrt(x + 1)*sqrt(x - 1)
"""
GinacFunction.__init__(self, "sinh", latex_name=r"\sinh")
def __init__(self):
"""
The cosine function.
EXAMPLES::
sage: cos(pi)
-1
sage: cos(x).subs(x==pi)
-1
sage: cos(2).n(100)
-0.41614683654714238699756822950
sage: loads(dumps(cos))
cos
We can prevent evaluation using the ``hold`` parameter::
sage: cos(0,hold=True)
cos(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = cos(0,hold=True); a.simplify()
1
TESTS::
sage: conjugate(cos(x))
cos(conjugate(x))
"""
GinacFunction.__init__(self, "cos", latex_name=r"\cos",
conversions=dict(maxima='cos',mathematica='Cos'))
def __init__(self):
"""
The arcsine function.
EXAMPLES::
sage: arcsin(0.5)
0.523598775598299
sage: arcsin(1/2)
1/6*pi
sage: arcsin(1 + 1.0*I)
0.666239432492515 + 1.06127506190504*I
We can delay evaluation using the ``hold`` parameter::
sage: arcsin(0,hold=True)
arcsin(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = arcsin(0,hold=True); a.simplify()
0
``conjugate(arcsin(x))==arcsin(conjugate(x))``, unless on the branch
cuts which run along the real axis outside the interval [-1, +1].::
sage: conjugate(arcsin(x))
conjugate(arcsin(x))
sage: var('y', domain='positive')
y
sage: conjugate(arcsin(y))
conjugate(arcsin(y))
sage: conjugate(arcsin(y+I))
conjugate(arcsin(y + I))
sage: conjugate(arcsin(1/16))
arcsin(1/16)
sage: conjugate(arcsin(2))
conjugate(arcsin(2))
sage: conjugate(arcsin(-2))
-conjugate(arcsin(2))
TESTS::
sage: arcsin(x)._sympy_()
asin(x)
sage: arcsin(x).operator()
arcsin
sage: asin(complex(1,1))
(0.6662394324925152+1.0612750619050357j)
Check that :trac:`22823` is fixed::
sage: bool(asin(SR(2.1)) == NaN)
True
sage: asin(SR(2.1)).is_real()
False
"""
GinacFunction.__init__(self, 'arcsin', latex_name=r"\arcsin",
conversions=dict(maxima='asin', sympy='asin', fricas="asin", giac="asin"))
def __init__(self):
"""
The arctangent function.
EXAMPLES::
sage: arctan(1/2)
arctan(1/2)
sage: RDF(arctan(1/2)) # rel tol 1e-15
0.46364760900080615
sage: arctan(1 + I)
arctan(I + 1)
sage: arctan(1/2).n(100)
0.46364760900080611621425623146
We can delay evaluation using the ``hold`` parameter::
sage: arctan(0,hold=True)
arctan(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = arctan(0,hold=True); a.simplify()
0
``conjugate(arctan(x))==arctan(conjugate(x))``, unless on the branch
cuts which run along the imaginary axis outside the interval [-I, +I].::
sage: conjugate(arctan(x))
conjugate(arctan(x))
sage: var('y', domain='positive')
y
sage: conjugate(arctan(y))
arctan(y)
sage: conjugate(arctan(y+I))
conjugate(arctan(y + I))
sage: conjugate(arctan(1/16))
arctan(1/16)
sage: conjugate(arctan(-2*I))
conjugate(arctan(-2*I))
sage: conjugate(arctan(2*I))
conjugate(arctan(2*I))
sage: conjugate(arctan(I/2))
arctan(-1/2*I)
TESTS::
sage: arctan(x).operator()
arctan
Check that :trac:`19918` is fixed::
sage: arctan(-x).subs(x=oo)
-1/2*pi
sage: arctan(-x).subs(x=-oo)
1/2*pi
"""
GinacFunction.__init__(self, "arctan", latex_name=r'\arctan',
conversions=dict(maxima='atan', sympy='atan'))
def __init__(self):
r"""
The hyperbolic cosine function.
EXAMPLES::
sage: cosh(pi)
cosh(pi)
sage: cosh(3.1415)
11.5908832931176
sage: float(cosh(pi))
11.591953275521519
sage: RR(cosh(1/2))
1.12762596520638
sage: latex(cosh(x))
\cosh\left(x\right)
To prevent automatic evaluation, use the ``hold`` parameter::
sage: cosh(arcsinh(x),hold=True)
cosh(arcsinh(x))
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: cosh(arcsinh(x),hold=True).simplify()
sqrt(x^2 + 1)
"""
GinacFunction.__init__(self, "cosh", latex_name=r"\cosh")
def __init__(self):
r"""
The Heaviside step function, ``heaviside(x)``.
INPUT:
- ``x`` - a real number or a symbolic expression
EXAMPLES::
sage: heaviside(-1)
0
sage: heaviside(1)
1
sage: heaviside(0)
heaviside(0)
sage: heaviside(x)
heaviside(x)
sage: latex(heaviside(x))
H\left(x\right)
sage: heaviside(x)._sympy_()
Heaviside(x)
sage: heaviside(x)._giac_()
Heaviside(x)
sage: h(x) = heaviside(x)
sage: h(pi).numerical_approx()
1.00000000000000
"""
GinacFunction.__init__(self, "heaviside", latex_name="H",
conversions=dict(maxima='hstep',
mathematica='HeavisideTheta',
sympy='Heaviside',
giac='Heaviside'))
def __init__(self):
"""
The sine function.
EXAMPLES::
sage: sin(0)
0
sage: sin(x).subs(x==0)
0
sage: sin(2).n(100)
0.90929742682568169539601986591
sage: loads(dumps(sin))
sin
We can prevent evaluation using the ``hold`` parameter::
sage: sin(0,hold=True)
sin(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = sin(0,hold=True); a.simplify()
0
TESTS::
sage: conjugate(sin(x))
sin(conjugate(x))
"""
GinacFunction.__init__(self, "sin", latex_name=r"\sin",
conversions=dict(maxima='sin',mathematica='Sin'))
def __init__(self):
r"""
The hyperbolic tangent function.
EXAMPLES::
sage: tanh(pi)
tanh(pi)
sage: tanh(3.1415)
0.996271386633702
sage: float(tanh(pi))
0.99627207622075
sage: tan(3.1415/4)
0.999953674278156
sage: tanh(pi/4)
tanh(1/4*pi)
sage: RR(tanh(1/2))
0.462117157260010
::
sage: CC(tanh(pi + I*e))
0.997524731976164 - 0.00279068768100315*I
sage: ComplexField(100)(tanh(pi + I*e))
0.99752473197616361034204366446 - 0.0027906876810031453884245163923*I
sage: CDF(tanh(pi + I*e)) # rel tol 2e-15
0.9975247319761636 - 0.002790687681003147*I
To prevent automatic evaluation, use the ``hold`` parameter::
sage: tanh(arcsinh(x),hold=True)
tanh(arcsinh(x))
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: tanh(arcsinh(x),hold=True).simplify()
x/sqrt(x^2 + 1)
TESTS::
sage: latex(tanh(x))
\tanh\left(x\right)
sage: tanh(x)._sympy_()
tanh(x)
Check that real/imaginary parts are correct (:trac:`20098`)::
sage: tanh(1+2*I).n()
1.16673625724092 - 0.243458201185725*I
sage: tanh(1+2*I).real().n()
1.16673625724092
sage: tanh(1+2*I).imag().n()
-0.243458201185725
sage: tanh(x).real()
sinh(2*real_part(x))/(cos(2*imag_part(x)) + cosh(2*real_part(x)))
sage: tanh(x).imag()
sin(2*imag_part(x))/(cos(2*imag_part(x)) + cosh(2*real_part(x)))
"""
GinacFunction.__init__(self, "tanh", latex_name=r"\tanh")
def __init__(self):
r"""
The unit step function, ``unit_step(x)``.
INPUT:
- ``x`` - a real number or a symbolic expression
EXAMPLES::
sage: unit_step(-1)
0
sage: unit_step(1)
1
sage: unit_step(0)
1
sage: unit_step(x)
unit_step(x)
sage: latex(unit_step(x))
\mathrm{u}\left(x\right)
TESTS::
sage: t = loads(dumps(unit_step(x)+1)); t
unit_step(x) + 1
sage: t.subs(x=0)
2
"""
GinacFunction.__init__(self, "unit_step", latex_name=r"\mathrm{u}",
conversions=dict(mathematica='UnitStep'))
def __init__(self):
r"""
The cotangent function.
EXAMPLES::
sage: cot(pi/4)
1
sage: RR(cot(pi/4))
1.00000000000000
sage: cot(1/2)
cot(1/2)
sage: cot(0.5)
1.83048772171245
sage: latex(cot(x))
\cot\left(x\right)
We can prevent evaluation using the ``hold`` parameter::
sage: cot(pi/4,hold=True)
cot(1/4*pi)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = cot(pi/4,hold=True); a.simplify()
1
EXAMPLES::
sage: cot(pi/4)
1
sage: cot(x).subs(x==pi/4)
1
sage: cot(pi/7)
cot(1/7*pi)
sage: cot(x)
cot(x)
sage: n(cot(pi/4),100)
1.0000000000000000000000000000
sage: float(cot(1))
0.64209261593433...
sage: bool(diff(cot(x), x) == diff(1/tan(x), x))
True
sage: diff(cot(x), x)
-cot(x)^2 - 1
TESTS:
Test complex input::
sage: cot(complex(1,1)) # rel tol 1e-15
(0.21762156185440273-0.8680141428959249j)
sage: cot(1.+I)
0.217621561854403 - 0.868014142895925*I
"""
GinacFunction.__init__(self, "cot", latex_name=r"\cot")
def __init__(self):
"""
The cosine function.
EXAMPLES::
sage: cos(pi)
-1
sage: cos(x).subs(x==pi)
-1
sage: cos(2).n(100)
-0.41614683654714238699756822950
sage: loads(dumps(cos))
cos
sage: cos(x)._sympy_()
cos(x)
We can prevent evaluation using the ``hold`` parameter::
sage: cos(0,hold=True)
cos(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = cos(0,hold=True); a.simplify()
1
If possible, the argument is also reduced modulo the
period length `2\pi`, and well-known identities are
directly evaluated::
sage: k = var('k', domain='integer')
sage: cos(1 + 2*k*pi)
cos(1)
sage: cos(k*pi)
cos(pi*k)
sage: cos(pi/3 + 2*k*pi)
1/2
TESTS::
sage: conjugate(cos(x))
cos(conjugate(x))
sage: cos(complex(1,1)) # rel tol 1e-15
(0.8337300251311491-0.9888977057628651j)
Check that :trac:`20752` is fixed::
sage: cos(3*pi+41/42*pi)
cos(1/42*pi)
sage: cos(-5*pi+1/42*pi)
-cos(1/42*pi)
sage: cos(pi-1/42*pi)
-cos(1/42*pi)
"""
GinacFunction.__init__(self, 'cos', latex_name=r"\cos",
conversions=dict(maxima='cos',mathematica='Cos',giac='cos'))
def __init__(self):
r"""
The inverse of the hyperbolic sine function.
EXAMPLES::
sage: asinh
arcsinh
sage: asinh(0.5)
0.481211825059603
sage: asinh(1/2)
arcsinh(1/2)
sage: asinh(1 + I*1.0)
1.06127506190504 + 0.666239432492515*I
To prevent automatic evaluation use the ``hold`` argument::
sage: asinh(-2,hold=True)
arcsinh(-2)
To then evaluate again, use the ``unhold`` method::
sage: asinh(-2,hold=True).unhold()
-arcsinh(2)
``conjugate(asinh(x))==asinh(conjugate(x))`` unless on the branch
cuts which run along the imaginary axis outside the interval [-I, +I].::
sage: conjugate(asinh(x))
conjugate(arcsinh(x))
sage: var('y', domain='positive')
y
sage: conjugate(asinh(y))
arcsinh(y)
sage: conjugate(asinh(y+I))
conjugate(arcsinh(y + I))
sage: conjugate(asinh(1/16))
arcsinh(1/16)
sage: conjugate(asinh(I/2))
arcsinh(-1/2*I)
sage: conjugate(asinh(2*I))
conjugate(arcsinh(2*I))
TESTS::
sage: asinh(x).operator()
arcsinh
sage: latex(asinh(x))
\operatorname{arsinh}\left(x\right)
sage: asinh(x)._sympy_()
asinh(x)
"""
GinacFunction.__init__(self, "arcsinh",
latex_name=r"\operatorname{arsinh}",
conversions=dict(maxima='asinh', sympy='asinh', fricas='asinh',
giac='asinh'))
def __init__(self):
r"""
The polylog function
`\text{Li}_n(z) = \sum_{k=1}^{\infty} z^k / k^n`.
INPUT:
- ``n`` - object
- ``z`` - object
EXAMPLES::
sage: polylog(1, x)
-log(-x + 1)
sage: polylog(2,1)
1/6*pi^2
sage: polylog(2,x^2+1)
polylog(2, x^2 + 1)
sage: polylog(4,0.5)
polylog(4, 0.500000000000000)
sage: f = polylog(4, 1); f
1/90*pi^4
sage: f.n()
1.08232323371114
sage: polylog(4, 2).n()
2.42786280675470 - 0.174371300025453*I
sage: complex(polylog(4,2))
(2.4278628067547032-0.17437130002545306j)
sage: float(polylog(4,0.5))
0.5174790616738993
sage: z = var('z')
sage: polylog(2,z).series(z==0, 5)
1*z + 1/4*z^2 + 1/9*z^3 + 1/16*z^4 + Order(z^5)
sage: loads(dumps(polylog))
polylog
sage: latex(polylog(5, x))
{\rm Li}_{5}(x)
TESTS:
Check if #8459 is fixed::
sage: t = maxima(polylog(5,x)).sage(); t
polylog(5, x)
sage: t.operator() == polylog
True
sage: t.subs(x=.5).n()
0.508400579242269
"""
GinacFunction.__init__(self, "polylog", nargs=2)
def __init__(self):
"""
The tangent function.
EXAMPLES::
sage: tan(pi)
0
sage: tan(3.1415)
-0.0000926535900581913
sage: tan(3.1415/4)
0.999953674278156
sage: tan(pi/4)
1
sage: tan(1/2)
tan(1/2)
sage: RR(tan(1/2))
0.546302489843790
We can prevent evaluation using the ``hold`` parameter::
sage: tan(pi/4,hold=True)
tan(1/4*pi)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = tan(pi/4,hold=True); a.simplify()
1
If possible, the argument is also reduced modulo the
period length `\pi`, and well-known identities are
directly evaluated::
sage: k = var('k', domain='integer')
sage: tan(1 + 2*k*pi)
tan(1)
sage: tan(k*pi)
0
TESTS::
sage: tan(x)._sympy_()
tan(x)
sage: conjugate(tan(x))
tan(conjugate(x))
sage: tan(complex(1,1)) # rel tol 1e-15
(0.2717525853195118+1.0839233273386946j)
Check that :trac:`19791` is fixed::
sage: tan(2+I).imag().n()
1.16673625724092
"""
GinacFunction.__init__(self, 'tan', latex_name=r"\tan")
def __init__(self):
"""
The arccosine function.
EXAMPLES::
sage: arccos(0.5)
1.04719755119660
sage: arccos(1/2)
1/3*pi
sage: arccos(1 + 1.0*I)
0.904556894302381 - 1.06127506190504*I
sage: arccos(3/4).n(100)
0.72273424781341561117837735264
We can delay evaluation using the ``hold`` parameter::
sage: arccos(0,hold=True)
arccos(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = arccos(0,hold=True); a.simplify()
1/2*pi
``conjugate(arccos(x))==arccos(conjugate(x))``, unless on the branch
cuts, which run along the real axis outside the interval [-1, +1].::
sage: conjugate(arccos(x))
conjugate(arccos(x))
sage: var('y', domain='positive')
y
sage: conjugate(arccos(y))
conjugate(arccos(y))
sage: conjugate(arccos(y+I))
conjugate(arccos(y + I))
sage: conjugate(arccos(1/16))
arccos(1/16)
sage: conjugate(arccos(2))
conjugate(arccos(2))
sage: conjugate(arccos(-2))
pi - conjugate(arccos(2))
TESTS::
sage: arccos(x)._sympy_()
acos(x)
sage: arccos(x).operator()
arccos
sage: acos(complex(1,1))
(0.9045568943023814-1.0612750619050357j)
"""
GinacFunction.__init__(self, 'arccos', latex_name=r"\arccos",
conversions=dict(maxima='acos', sympy='acos'))
def __init__(self):
r"""
Riemann zeta function at s with s a real or complex number.
INPUT:
- ``s`` - real or complex number
If s is a real number the computation is done using the MPFR
library. When the input is not real, the computation is done using
the PARI C library.
EXAMPLES::
sage: zeta(x)
zeta(x)
sage: zeta(2)
1/6*pi^2
sage: zeta(2.)
1.64493406684823
sage: RR = RealField(200)
sage: zeta(RR(2))
1.6449340668482264364724151666460251892189499012067984377356
sage: zeta(I)
zeta(I)
sage: zeta(I).n()
0.00330022368532410 - 0.418155449141322*I
It is possible to use the ``hold`` argument to prevent
automatic evaluation::
sage: zeta(2,hold=True)
zeta(2)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = zeta(2,hold=True); a.simplify()
1/6*pi^2
TESTS::
sage: latex(zeta(x))
\zeta(x)
sage: a = loads(dumps(zeta(x)))
sage: a.operator() == zeta
True
sage: zeta(1)
Infinity
sage: zeta(x).subs(x=1)
Infinity
"""
GinacFunction.__init__(self, "zeta")
def __init__(self):
r"""
The inverse of the hyperbolic tangent function.
EXAMPLES::
sage: atanh(0.5)
0.549306144334055
sage: atanh(1/2)
1/2*log(3)
sage: atanh(1 + I*1.0)
0.402359478108525 + 1.01722196789785*I
To prevent automatic evaluation use the ``hold`` argument::
sage: atanh(-1/2,hold=True)
arctanh(-1/2)
To then evaluate again, use the ``unhold`` method::
sage: atanh(-1/2,hold=True).unhold()
-1/2*log(3)
``conjugate(arctanh(x))==arctanh(conjugate(x))`` unless on the branch
cuts which run along the real axis outside the interval [-1, +1].::
sage: conjugate(atanh(x))
conjugate(arctanh(x))
sage: var('y', domain='positive')
y
sage: conjugate(atanh(y))
conjugate(arctanh(y))
sage: conjugate(atanh(y+I))
conjugate(arctanh(y + I))
sage: conjugate(atanh(1/16))
1/2*log(17/15)
sage: conjugate(atanh(I/2))
arctanh(-1/2*I)
sage: conjugate(atanh(-2*I))
arctanh(2*I)
TESTS::
sage: atanh(x).operator()
arctanh
sage: latex(atanh(x))
\operatorname{artanh}\left(x\right)
sage: atanh(x)._sympy_()
atanh(x)
"""
GinacFunction.__init__(self, "arctanh",
latex_name=r"\operatorname{artanh}",
conversions=dict(maxima='atanh', sympy='atanh', fricas='atanh',
giac='atanh'))
def __init__(self):
"""
TESTS::
sage: from sage.functions.log import logb
sage: loads(dumps(logb))
log
"""
GinacFunction.__init__(self, 'log', ginac_name='logb', nargs=2,
latex_name=r'\log',
conversions=dict(maxima='log'))
def __init__(self):
"""
TESTS::
sage: loads(dumps(exp))
exp
sage: maxima(exp(x))._sage_()
e^x
"""
GinacFunction.__init__(self, "exp", latex_name=r"\exp",
conversions=dict(maxima='exp', fricas='exp'))
def __init__(self):
r"""
The dilogarithm function
`\text{Li}_2(z) = \sum_{k=1}^{\infty} z^k / k^2`.
This is simply an alias for polylog(2, z).
EXAMPLES::
sage: dilog(1)
1/6*pi^2
sage: dilog(1/2)
1/12*pi^2 - 1/2*log(2)^2
sage: dilog(x^2+1)
dilog(x^2 + 1)
sage: dilog(-1)
-1/12*pi^2
sage: dilog(-1.1)
-0.890838090262283
sage: float(dilog(1))
1.6449340668482262
sage: var('z')
z
sage: dilog(z).diff(z, 2)
log(-z + 1)/z^2 - 1/((z - 1)*z)
sage: dilog(z).series(z==1/2, 3)
(1/12*pi^2 - 1/2*log(2)^2) + (-2*log(1/2))*(z - 1/2) + (2*log(1/2) + 2)*(z - 1/2)^2 + Order(1/8*(2*z - 1)^3)
sage: latex(dilog(z))
{\rm Li}_2\left(z\right)
TESTS:
``conjugate(dilog(x))==dilog(conjugate(x))`` unless on the branch cuts
which run along the positive real axis beginning at 1.::
sage: conjugate(dilog(x))
conjugate(dilog(x))
sage: var('y',domain='positive')
y
sage: conjugate(dilog(y))
conjugate(dilog(y))
sage: conjugate(dilog(1/19))
dilog(1/19)
sage: conjugate(dilog(1/2*I))
dilog(-1/2*I)
sage: dilog(conjugate(1/2*I))
dilog(-1/2*I)
sage: conjugate(dilog(2))
conjugate(dilog(2))
"""
GinacFunction.__init__(self, 'dilog',
conversions=dict(maxima='li[2]'))
def __init__(self):
r"""
The Gamma function. This is defined by
.. MATH::
\Gamma(z) = \int_0^\infty t^{z-1}e^{-t} dt
for complex input `z` with real part greater than zero, and by
analytic continuation on the rest of the complex plane (except
for negative integers, which are poles).
It is computed by various libraries within Sage, depending on
the input type.
EXAMPLES::
sage: from sage.functions.gamma import gamma1
sage: gamma1(CDF(0.5,14))
-4.0537030780372815e-10 - 5.773299834553605e-10*I
sage: gamma1(CDF(I))
-0.15494982830181067 - 0.49801566811835607*I
Recall that `\Gamma(n)` is `n-1` factorial::
sage: gamma1(11) == factorial(10)
True
sage: gamma1(6)
120
sage: gamma1(1/2)
sqrt(pi)
sage: gamma1(-1)
Infinity
sage: gamma1(I)
gamma(I)
sage: gamma1(x/2)(x=5)
3/4*sqrt(pi)
sage: gamma1(float(6)) # For ARM: rel tol 3e-16
120.0
sage: gamma(6.)
120.000000000000
sage: gamma1(x)
gamma(x)
::
sage: gamma1(pi)
gamma(pi)
sage: gamma1(i)
gamma(I)
sage: gamma1(i).n()
-0.154949828301811 - 0.498015668118356*I
sage: gamma1(int(5))
24
::
sage: conjugate(gamma(x))
gamma(conjugate(x))
::
sage: plot(gamma1(x),(x,1,5))
Graphics object consisting of 1 graphics primitive
To prevent automatic evaluation use the ``hold`` argument::
sage: gamma1(1/2,hold=True)
gamma(1/2)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: gamma1(1/2,hold=True).simplify()
sqrt(pi)
TESTS:
sage: gamma(x)._sympy_()
gamma(x)
We verify that we can convert this function to Maxima and
convert back to Sage::
sage: z = var('z')
sage: maxima(gamma1(z)).sage()
gamma(z)
sage: latex(gamma1(z))
\Gamma\left(z\right)
Test that :trac:`5556` is fixed::
sage: gamma1(3/4)
gamma(3/4)
sage: gamma1(3/4).n(100)
1.2254167024651776451290983034
Check that negative integer input works::
sage: (-1).gamma()
Infinity
sage: (-1.).gamma()
NaN
sage: CC(-1).gamma()
Infinity
sage: RDF(-1).gamma()
NaN
sage: CDF(-1).gamma()
Infinity
Check if :trac:`8297` is fixed::
sage: latex(gamma(1/4))
\Gamma\left(\frac{1}{4}\right)
Test pickling::
sage: loads(dumps(gamma(x)))
gamma(x)
Check that the implementations roughly agrees (note there might be
difference of several ulp on more complicated entries)::
sage: import mpmath
sage: float(gamma(10.)) == gamma(10.r) == float(gamma(mpmath.mpf(10)))
True
sage: float(gamma(8.5)) == gamma(8.5r) == float(gamma(mpmath.mpf(8.5)))
True
Check that ``QQbar`` half integers work with the ``pi`` formula::
sage: gamma(QQbar(1/2))
sqrt(pi)
sage: gamma(QQbar(-9/2))
-32/945*sqrt(pi)
.. SEEALSO::
:meth:`gamma`
"""
GinacFunction.__init__(self,
'gamma',
latex_name=r"\Gamma",
ginac_name='gamma',
conversions={
'mathematica': 'Gamma',
'maple': 'GAMMA',
'sympy': 'gamma',
'fricas': 'Gamma',
'giac': 'Gamma'
})
def __init__(self):
r"""
Riemann zeta function at s with s a real or complex number.
INPUT:
- ``s`` - real or complex number
If s is a real number the computation is done using the MPFR
library. When the input is not real, the computation is done using
the PARI C library.
EXAMPLES::
sage: zeta(x)
zeta(x)
sage: zeta(2)
1/6*pi^2
sage: zeta(2.)
1.64493406684823
sage: RR = RealField(200)
sage: zeta(RR(2))
1.6449340668482264364724151666460251892189499012067984377356
sage: zeta(I)
zeta(I)
sage: zeta(I).n()
0.00330022368532410 - 0.418155449141322*I
It is possible to use the ``hold`` argument to prevent
automatic evaluation::
sage: zeta(2,hold=True)
zeta(2)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = zeta(2,hold=True); a.simplify()
1/6*pi^2
Check that :trac:`15846` is resolved::
sage: zeta(x).series(x==1, 1)
1*(x - 1)^(-1) + (euler_gamma + log(2) + log(pi) + 2*zetaderiv(1, 0)) + Order(x - 1)
sage: zeta(x).residue(x==1)
1
TESTS::
sage: latex(zeta(x))
\zeta(x)
sage: a = loads(dumps(zeta(x)))
sage: a.operator() == zeta
True
sage: zeta(1)
Infinity
sage: zeta(x).subs(x=1)
Infinity
"""
GinacFunction.__init__(self, "zeta")
def __init__(self):
r"""
Returns the complex conjugate of the input.
It is possible to prevent automatic evaluation using the
``hold`` parameter::
sage: conjugate(I,hold=True)
conjugate(I)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: conjugate(I,hold=True).simplify()
-I
TESTS::
sage: x,y = var('x,y')
sage: x.conjugate()
conjugate(x)
sage: latex(conjugate(x))
\overline{x}
sage: f = function('f')
sage: latex(f(x).conjugate())
\overline{f\left(x\right)}
sage: f = function('psi',x,y)
sage: latex(f.conjugate())
\overline{\psi\left(x, y\right)}
sage: x.conjugate().conjugate()
x
sage: x.conjugate().operator()
conjugate
sage: x.conjugate().operator() == conjugate
True
Check if #8755 is fixed::
sage: conjugate(sqrt(-3))
conjugate(sqrt(-3))
sage: conjugate(sqrt(3))
sqrt(3)
sage: conjugate(sqrt(x))
conjugate(sqrt(x))
sage: conjugate(x^2)
conjugate(x)^2
sage: var('y',domain='positive')
y
sage: conjugate(sqrt(y))
sqrt(y)
Check if #10964 is fixed::
sage: z= I*sqrt(-3); z
I*sqrt(-3)
sage: conjugate(z)
-I*conjugate(sqrt(-3))
sage: var('a')
a
sage: conjugate(a*sqrt(-2)*sqrt(-3))
conjugate(a)*conjugate(sqrt(-3))*conjugate(sqrt(-2))
"""
GinacFunction.__init__(self, "conjugate")
def __init__(self):
r"""
Return the beta function. This is defined by
.. MATH::
\operatorname{B}(p,q) = \int_0^1 t^{p-1}(1-t)^{q-1} dt
for complex or symbolic input `p` and `q`.
Note that the order of inputs does not matter:
`\operatorname{B}(p,q)=\operatorname{B}(q,p)`.
GiNaC is used to compute `\operatorname{B}(p,q)`. However, complex inputs
are not yet handled in general. When GiNaC raises an error on
such inputs, we raise a NotImplementedError.
If either input is 1, GiNaC returns the reciprocal of the
other. In other cases, GiNaC uses one of the following
formulas:
.. MATH::
\operatorname{B}(p,q) = \frac{\Gamma(p)\Gamma(q)}{\Gamma(p+q)}
or
.. MATH::
\operatorname{B}(p,q) = (-1)^q \operatorname{B}(1-p-q, q).
For numerical inputs, GiNaC uses the formula
.. MATH::
\operatorname{B}(p,q) = \exp[\log\Gamma(p)+\log\Gamma(q)-\log\Gamma(p+q)]
INPUT:
- ``p`` - number or symbolic expression
- ``q`` - number or symbolic expression
OUTPUT: number or symbolic expression (if input is symbolic)
EXAMPLES::
sage: beta(3,2)
1/12
sage: beta(3,1)
1/3
sage: beta(1/2,1/2)
beta(1/2, 1/2)
sage: beta(-1,1)
-1
sage: beta(-1/2,-1/2)
0
sage: ex = beta(x/2,3)
sage: set(ex.operands()) == set([1/2*x, 3])
True
sage: beta(.5,.5)
3.14159265358979
sage: beta(1,2.0+I)
0.400000000000000 - 0.200000000000000*I
sage: ex = beta(3,x+I)
sage: set(ex.operands()) == set([x+I, 3])
True
The result is symbolic if exact input is given::
sage: ex = beta(2,1+5*I); ex
beta(...
sage: set(ex.operands()) == set([1+5*I, 2])
True
sage: beta(2, 2.)
0.166666666666667
sage: beta(I, 2.)
-0.500000000000000 - 0.500000000000000*I
sage: beta(2., 2)
0.166666666666667
sage: beta(2., I)
-0.500000000000000 - 0.500000000000000*I
sage: beta(x, x)._sympy_()
beta(x, x)
Test pickling::
sage: loads(dumps(beta))
beta
Check that :trac:`15196` is fixed::
sage: beta(-1.3,-0.4)
-4.92909641669610
"""
GinacFunction.__init__(self,
'beta',
nargs=2,
latex_name=r"\operatorname{B}",
conversions=dict(maxima='beta',
mathematica='Beta',
sympy='beta',
fricas='Beta',
giac='Beta'))
def __init__(self):
r"""
The inverse of the hyperbolic cosine function.
EXAMPLES::
sage: acosh(1/2)
arccosh(1/2)
sage: acosh(1 + I*1.0)
1.06127506190504 + 0.904556894302381*I
sage: float(acosh(2))
1.3169578969248168
sage: cosh(float(acosh(2)))
2.0
sage: acosh(complex(1, 2)) # abs tol 1e-15
(1.5285709194809982+1.1437177404024204j)
.. warning::
If the input is in the complex field or symbolic (which
includes rational and integer input), the output will
be complex. However, if the input is a real decimal, the
output will be real or `NaN`. See the examples for details.
::
sage: acosh(0.5)
NaN
sage: acosh(1/2)
arccosh(1/2)
sage: acosh(1/2).n()
NaN
sage: acosh(CC(0.5))
1.04719755119660*I
sage: acosh(0)
1/2*I*pi
sage: acosh(-1)
I*pi
To prevent automatic evaluation use the ``hold`` argument::
sage: acosh(-1,hold=True)
arccosh(-1)
To then evaluate again, use the ``unhold`` method::
sage: acosh(-1,hold=True).unhold()
I*pi
``conjugate(arccosh(x))==arccosh(conjugate(x))`` unless on the branch
cut which runs along the real axis from +1 to -inf.::
sage: conjugate(acosh(x))
conjugate(arccosh(x))
sage: var('y', domain='positive')
y
sage: conjugate(acosh(y))
conjugate(arccosh(y))
sage: conjugate(acosh(y+I))
conjugate(arccosh(y + I))
sage: conjugate(acosh(1/16))
conjugate(arccosh(1/16))
sage: conjugate(acosh(2))
arccosh(2)
sage: conjugate(acosh(I/2))
arccosh(-1/2*I)
TESTS::
sage: acosh(x).operator()
arccosh
sage: latex(acosh(x))
\operatorname{arcosh}\left(x\right)
sage: acosh(x)._sympy_()
acosh(x)
"""
GinacFunction.__init__(self,
"arccosh",
latex_name=r"\operatorname{arcosh}",
conversions=dict(maxima='acosh',
sympy='acosh',
fricas='acosh',
giac='acosh',
mathematica='ArcCosh'))
def __init__(self):
r"""
Derivatives of the digamma function `\psi(x)`. T
EXAMPLES::
sage: from sage.functions.gamma import psi2
sage: psi2(2, x)
psi(2, x)
sage: psi2(2, x).derivative(x)
psi(3, x)
sage: n = var('n')
sage: psi2(n, x).derivative(x)
psi(n + 1, x)
::
sage: psi2(0, x)
psi(x)
sage: psi2(-1, x)
log(gamma(x))
sage: psi2(3, 1)
1/15*pi^4
::
sage: psi2(2, .5).n()
-16.8287966442343
sage: psi2(2, .5).n(100)
-16.828796644234319995596334261
TESTS::
sage: psi2(n, x).derivative(n)
Traceback (most recent call last):
...
RuntimeError: cannot diff psi(n,x) with respect to n
sage: latex(psi2(2,x))
\psi\left(2, x\right)
sage: loads(dumps(psi2(2,x)+1))
psi(2, x) + 1
sage: psi(2, x)._sympy_()
polygamma(2, x)
sage: psi(2, x)._fricas_() # optional - fricas
polygamma(2,x)
Fixed conversion::
sage: psi(2,x)._maple_init_()
'Psi(2,x)'
"""
GinacFunction.__init__(self,
"psi",
nargs=2,
latex_name=r'\psi',
conversions=dict(mathematica='PolyGamma',
sympy='polygamma',
maple='Psi',
giac='Psi',
fricas='polygamma'))
def __init__(self):
r"""
The exponential function, `\exp(x) = e^x`.
EXAMPLES::
sage: exp(-1)
e^(-1)
sage: exp(2)
e^2
sage: exp(2).n(100)
7.3890560989306502272304274606
sage: exp(x^2 + log(x))
e^(x^2 + log(x))
sage: exp(x^2 + log(x)).simplify()
x*e^(x^2)
sage: exp(2.5)
12.1824939607035
sage: exp(float(2.5))
12.182493960703473
sage: exp(RDF('2.5'))
12.182493960703473
sage: exp(I*pi/12)
(1/4*I + 1/4)*sqrt(6) - (1/4*I - 1/4)*sqrt(2)
To prevent automatic evaluation, use the ``hold`` parameter::
sage: exp(I*pi,hold=True)
e^(I*pi)
sage: exp(0,hold=True)
e^0
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: exp(0,hold=True).simplify()
1
::
sage: exp(pi*I/2)
I
sage: exp(pi*I)
-1
sage: exp(8*pi*I)
1
sage: exp(7*pi*I/2)
-I
For the sake of simplification, the argument is reduced modulo the
period of the complex exponential function, `2\pi i`::
sage: k = var('k', domain='integer')
sage: exp(2*k*pi*I)
1
sage: exp(log(2) + 2*k*pi*I)
2
The precision for the result is deduced from the precision of
the input. Convert the input to a higher precision explicitly
if a result with higher precision is desired::
sage: t = exp(RealField(100)(2)); t
7.3890560989306502272304274606
sage: t.prec()
100
sage: exp(2).n(100)
7.3890560989306502272304274606
TESTS::
sage: latex(exp(x))
e^{x}
sage: latex(exp(sqrt(x)))
e^{\sqrt{x}}
sage: latex(exp)
\exp
sage: latex(exp(sqrt(x))^x)
\left(e^{\sqrt{x}}\right)^{x}
sage: latex(exp(sqrt(x)^x))
e^{\left(\sqrt{x}^{x}\right)}
sage: exp(x)._sympy_()
exp(x)
Test conjugates::
sage: conjugate(exp(x))
e^conjugate(x)
Test simplifications when taking powers of exp (:trac:`7264`)::
sage: var('a,b,c,II')
(a, b, c, II)
sage: model_exp = exp(II)**a*(b)
sage: sol1_l={b: 5.0, a: 1.1}
sage: model_exp.subs(sol1_l)
5.00000000000000*(e^II)^1.10000000000000
::
sage: exp(3)^II*exp(x)
(e^3)^II*e^x
sage: exp(x)*exp(x)
e^(2*x)
sage: exp(x)*exp(a)
e^(a + x)
sage: exp(x)*exp(a)^2
e^(2*a + x)
Another instance of the same problem (:trac:`7394`)::
sage: 2*sqrt(e)
2*sqrt(e)
Check that :trac:`19918` is fixed::
sage: exp(-x^2).subs(x=oo)
0
sage: exp(-x).subs(x=-oo)
+Infinity
"""
GinacFunction.__init__(self,
"exp",
latex_name=r"\exp",
conversions=dict(maxima='exp', fricas='exp'))
def __init__(self):
r"""
The cotangent function.
EXAMPLES::
sage: cot(pi/4)
1
sage: RR(cot(pi/4))
1.00000000000000
sage: cot(1/2)
cot(1/2)
sage: cot(0.5)
1.83048772171245
sage: latex(cot(x))
\cot\left(x\right)
sage: cot(x)._sympy_()
cot(x)
We can prevent evaluation using the ``hold`` parameter::
sage: cot(pi/4,hold=True)
cot(1/4*pi)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = cot(pi/4,hold=True); a.simplify()
1
EXAMPLES::
sage: cot(pi/4)
1
sage: cot(x).subs(x==pi/4)
1
sage: cot(pi/7)
cot(1/7*pi)
sage: cot(x)
cot(x)
sage: n(cot(pi/4),100)
1.0000000000000000000000000000
sage: float(cot(1))
0.64209261593433...
sage: bool(diff(cot(x), x) == diff(1/tan(x), x))
True
sage: diff(cot(x), x)
-cot(x)^2 - 1
TESTS::
sage: cot(float(0))
Infinity
sage: cot(SR(0))
Infinity
sage: cot(float(0.1))
9.966644423259238
sage: type(_)
<... 'float'>
sage: cot(float(0))
Infinity
sage: cot(SR(0))
Infinity
sage: cot(float(0.1))
9.966644423259238
sage: type(_)
<... 'float'>
Test complex input::
sage: cot(complex(1,1)) # rel tol 1e-15
(0.21762156185440273-0.8680141428959249j)
sage: cot(1.+I)
0.217621561854403 - 0.868014142895925*I
"""
GinacFunction.__init__(self, 'cot', latex_name=r"\cot")
def __init__(self):
r"""
The natural logarithm of x. See `log?` for
more information about its behavior.
EXAMPLES::
sage: ln(e^2)
2
sage: ln(2)
log(2)
sage: ln(10)
log(10)
::
sage: ln(RDF(10))
2.302585092994046
sage: ln(2.718)
0.999896315728952
sage: ln(2.0)
0.693147180559945
sage: ln(float(-1))
3.141592653589793j
sage: ln(complex(-1))
3.141592653589793j
The ``hold`` parameter can be used to prevent automatic evaluation::
sage: log(-1,hold=True)
log(-1)
sage: log(-1)
I*pi
sage: I.log(hold=True)
log(I)
sage: I.log(hold=True).simplify()
1/2*I*pi
TESTS::
sage: latex(x.log())
\log\left(x\right)
sage: latex(log(1/4))
\log\left(\frac{1}{4}\right)
sage: log(x)._sympy_()
log(x)
sage: loads(dumps(ln(x)+1))
log(x) + 1
``conjugate(log(x))==log(conjugate(x))`` unless on the branch cut which
runs along the negative real axis.::
sage: conjugate(log(x))
conjugate(log(x))
sage: var('y', domain='positive')
y
sage: conjugate(log(y))
log(y)
sage: conjugate(log(y+I))
conjugate(log(y + I))
sage: conjugate(log(-1))
-I*pi
sage: log(conjugate(-1))
I*pi
Check if float arguments are handled properly.::
sage: from sage.functions.log import function_log as log
sage: log(float(5))
1.6094379124341003
sage: log(float(0))
-inf
sage: log(float(-1))
3.141592653589793j
sage: log(x).subs(x=float(-1))
3.141592653589793j
:trac:`22142`::
sage: log(QQbar(sqrt(2)))
log(1.414213562373095?)
sage: log(QQbar(sqrt(2))*1.)
0.346573590279973
sage: polylog(QQbar(sqrt(2)),3)
polylog(1.414213562373095?, 3)
"""
GinacFunction.__init__(self,
'log',
latex_name=r'\log',
conversions=dict(maxima='log',
fricas='log',
mathematica='Log'))
def __call__(self, *args, **kwds):
"""
Return the logarithm of x to the given base.
Calls the ``log`` method of the object x when computing
the logarithm, thus allowing use of logarithm on any object
containing a ``log`` method. In other words, log works
on more than just real numbers.
EXAMPLES::
sage: log(e^2)
2
To change the base of the logarithm, add a second parameter::
sage: log(1000,10)
3
You can use
:class:`RDF<sage.rings.real_double.RealDoubleField_class>`,
:class:`~sage.rings.real_mpfr.RealField` or ``n`` to get a
numerical real approximation::
sage: log(1024, 2)
10
sage: RDF(log(1024, 2))
10.0
sage: log(10, 4)
log(10)/log(4)
sage: RDF(log(10, 4))
1.6609640474436813
sage: log(10, 2)
log(10)/log(2)
sage: n(log(10, 2))
3.32192809488736
sage: log(10, e)
log(10)
sage: n(log(10, e))
2.30258509299405
The log function works for negative numbers, complex
numbers, and symbolic numbers too, picking the branch
with angle between `-pi` and `pi`::
sage: log(-1+0*I)
I*pi
sage: log(CC(-1))
3.14159265358979*I
sage: log(-1.0)
3.14159265358979*I
For input zero, the following behavior occurs::
sage: log(0)
-Infinity
sage: log(CC(0))
-infinity
sage: log(0.0)
-infinity
The log function also works in finite fields as long as the
argument lies in the multiplicative group generated by the base::
sage: F = GF(13); g = F.multiplicative_generator(); g
2
sage: a = F(8)
sage: log(a,g); g^log(a,g)
3
8
sage: log(a,3)
Traceback (most recent call last):
...
ValueError: No discrete log of 8 found to base 3
sage: log(F(9), 3)
2
The log function also works for p-adics (see documentation for
p-adics for more information)::
sage: R = Zp(5); R
5-adic Ring with capped relative precision 20
sage: a = R(16); a
1 + 3*5 + O(5^20)
sage: log(a)
3*5 + 3*5^2 + 3*5^4 + 3*5^5 + 3*5^6 + 4*5^7 + 2*5^8 + 5^9 +
5^11 + 2*5^12 + 5^13 + 3*5^15 + 2*5^16 + 4*5^17 + 3*5^18 +
3*5^19 + O(5^20)
TESTS:
Check if :trac:`10136` is fixed::
sage: log(x).operator() is log
True
sage: log(x).operator() is ln
True
sage: log(1000, 10, base=5)
Traceback (most recent call last):
...
TypeError: Symbolic function log must be called as log(x),
log(x, base=b) or log(x, b)
"""
base = kwds.pop('base', None)
if base is None:
if len(args) == 1:
return GinacFunction.__call__(self, *args, **kwds)
# second argument is base
base = args[1]
args = args[:1]
if len(args) != 1:
raise TypeError("Symbolic function log must be called as "
"log(x), log(x, base=b) or log(x, b)")
try:
return args[0].log(base)
except (AttributeError, TypeError):
return GinacFunction.__call__(self, *args, **kwds) / \
GinacFunction.__call__(self, base, **kwds)
def __init__(self):
r"""
Riemann zeta function at s with s a real or complex number.
INPUT:
- ``s`` - real or complex number
If s is a real number the computation is done using the MPFR
library. When the input is not real, the computation is done using
the PARI C library.
EXAMPLES::
sage: zeta(x)
zeta(x)
sage: zeta(2)
1/6*pi^2
sage: zeta(2.)
1.64493406684823
sage: RR = RealField(200)
sage: zeta(RR(2))
1.6449340668482264364724151666460251892189499012067984377356
sage: zeta(I)
zeta(I)
sage: zeta(I).n()
0.00330022368532410 - 0.418155449141322*I
sage: zeta(sqrt(2))
zeta(sqrt(2))
sage: zeta(sqrt(2)).n() # rel tol 1e-10
3.02073767948603
It is possible to use the ``hold`` argument to prevent
automatic evaluation::
sage: zeta(2,hold=True)
zeta(2)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = zeta(2,hold=True); a.simplify()
1/6*pi^2
The Laurent expansion of `\zeta(s)` at `s=1` is
implemented by means of the
:wikipedia:`Stieltjes constants <Stieltjes_constants>`::
sage: s = SR('s')
sage: zeta(s).series(s==1, 2)
1*(s - 1)^(-1) + euler_gamma + (-stieltjes(1))*(s - 1) + Order((s - 1)^2)
Generally, the Stieltjes constants occur in the Laurent
expansion of `\zeta`-type singularities::
sage: zeta(2*s/(s+1)).series(s==1, 2)
2*(s - 1)^(-1) + (euler_gamma + 1) + (-1/2*stieltjes(1))*(s - 1) + Order((s - 1)^2)
TESTS::
sage: latex(zeta(x))
\zeta(x)
sage: a = loads(dumps(zeta(x)))
sage: a.operator() == zeta
True
sage: zeta(x)._sympy_()
zeta(x)
sage: zeta(1)
Infinity
sage: zeta(x).subs(x=1)
Infinity
Check that :trac:`19799` is resolved::
sage: zeta(pi)
zeta(pi)
sage: zeta(pi).n() # rel tol 1e-10
1.17624173838258
Check that :trac:`20082` is fixed::
sage: zeta(x).series(x==pi, 2)
(zeta(pi)) + (zetaderiv(1, pi))*(-pi + x) + Order((pi - x)^2)
sage: (zeta(x) * 1/(1 - exp(-x))).residue(x==2*pi*I)
zeta(2*I*pi)
Check that the right infinities are returned (:trac:`19439`)::
sage: zeta(1.0)
+infinity
sage: zeta(SR(1.0))
Infinity
"""
GinacFunction.__init__(self, 'zeta', conversions={'giac': 'Zeta'})
def __init__(self):
r"""
The inverse of the hyperbolic cosine function.
EXAMPLES::
sage: arccosh(1/2)
arccosh(1/2)
sage: arccosh(1 + I*1.0)
1.06127506190504 + 0.904556894302381*I
sage: float(arccosh(2))
1.3169578969248168
sage: cosh(float(arccosh(2)))
2.0
.. warning::
If the input is in the complex field or symbolic (which
includes rational and integer input), the output will
be complex. However, if the input is a real decimal, the
output will be real or `NaN`. See the examples for details.
::
sage: arccosh(0.5)
NaN
sage: arccosh(1/2)
arccosh(1/2)
sage: arccosh(1/2).n()
NaN
sage: arccosh(CC(0.5))
1.04719755119660*I
sage: arccosh(0)
1/2*I*pi
sage: arccosh(-1)
I*pi
To prevent automatic evaluation use the ``hold`` argument::
sage: arccosh(-1,hold=True)
arccosh(-1)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: arccosh(-1,hold=True).simplify()
I*pi
``conjugate(arccosh(x))==arccosh(conjugate(x))`` unless on the branch
cut which runs along the real axis from +1 to -inf.::
sage: conjugate(arccosh(x))
conjugate(arccosh(x))
sage: var('y', domain='positive')
y
sage: conjugate(arccosh(y))
conjugate(arccosh(y))
sage: conjugate(arccosh(y+I))
conjugate(arccosh(y + I))
sage: conjugate(arccosh(1/16))
conjugate(arccosh(1/16))
sage: conjugate(arccosh(2))
arccosh(2)
sage: conjugate(arccosh(I/2))
arccosh(-1/2*I)
TESTS::
sage: arccosh(x).operator()
arccosh
sage: latex(arccosh(x))
{\rm arccosh}\left(x\right)
"""
GinacFunction.__init__(self, "arccosh", latex_name=r"{\rm arccosh}",
conversions=dict(maxima='acosh', sympy='acosh'))
def __init__(self):
r"""
The principal branch of the log gamma function. Note that for
`x < 0`, ``log(gamma(x))`` is not, in general, equal to
``log_gamma(x)``.
It is computed by the ``log_gamma`` function for the number type,
or by ``lgamma`` in Ginac, failing that.
Gamma is defined for complex input `z` with real part greater
than zero, and by analytic continuation on the rest of the
complex plane (except for negative integers, which are poles).
EXAMPLES:
Numerical evaluation happens when appropriate, to the
appropriate accuracy (see :trac:`10072`)::
sage: log_gamma(6)
log(120)
sage: log_gamma(6.)
4.78749174278205
sage: log_gamma(6).n()
4.78749174278205
sage: log_gamma(RealField(100)(6))
4.7874917427820459942477009345
sage: log_gamma(2.4 + I)
-0.0308566579348816 + 0.693427705955790*I
sage: log_gamma(-3.1)
0.400311696703985 - 12.5663706143592*I
sage: log_gamma(-1.1) == log(gamma(-1.1))
False
Symbolic input works (see :trac:`10075`)::
sage: log_gamma(3*x)
log_gamma(3*x)
sage: log_gamma(3 + I)
log_gamma(I + 3)
sage: log_gamma(3 + I + x)
log_gamma(x + I + 3)
Check that :trac:`12521` is fixed::
sage: log_gamma(-2.1)
1.53171380819509 - 9.42477796076938*I
sage: log_gamma(CC(-2.1))
1.53171380819509 - 9.42477796076938*I
sage: log_gamma(-21/10).n()
1.53171380819509 - 9.42477796076938*I
sage: exp(log_gamma(-1.3) + log_gamma(-0.4) -
....: log_gamma(-1.3 - 0.4)).real_part() # beta(-1.3, -0.4)
-4.92909641669610
In order to prevent evaluation, use the ``hold`` argument;
to evaluate a held expression, use the ``n()`` numerical
evaluation method::
sage: log_gamma(SR(5), hold=True)
log_gamma(5)
sage: log_gamma(SR(5), hold=True).n()
3.17805383034795
TESTS::
sage: log_gamma(-2.1 + I)
-1.90373724496982 - 7.18482377077183*I
sage: log_gamma(pari(6))
4.78749174278205
sage: log_gamma(x)._sympy_()
loggamma(x)
sage: log_gamma(CC(6))
4.78749174278205
sage: log_gamma(CC(-2.5))
-0.0562437164976741 - 9.42477796076938*I
sage: log_gamma(RDF(-2.5))
-0.056243716497674054 - 9.42477796076938*I
sage: log_gamma(CDF(-2.5))
-0.056243716497674054 - 9.42477796076938*I
sage: log_gamma(float(-2.5))
(-0.056243716497674054-9.42477796076938j)
sage: log_gamma(complex(-2.5))
(-0.056243716497674054-9.42477796076938j)
``conjugate(log_gamma(x)) == log_gamma(conjugate(x))`` unless on the
branch cut, which runs along the negative real axis.::
sage: conjugate(log_gamma(x))
conjugate(log_gamma(x))
sage: var('y', domain='positive')
y
sage: conjugate(log_gamma(y))
log_gamma(y)
sage: conjugate(log_gamma(y + I))
conjugate(log_gamma(y + I))
sage: log_gamma(-2)
+Infinity
sage: conjugate(log_gamma(-2))
+Infinity
"""
GinacFunction.__init__(self,
"log_gamma",
latex_name=r'\log\Gamma',
conversions=dict(mathematica='LogGamma',
maxima='log_gamma',
sympy='loggamma',
fricas='logGamma'))
def __init__(self):
"""
The arccosine function.
EXAMPLES::
sage: arccos(0.5)
1.04719755119660
sage: arccos(1/2)
1/3*pi
sage: arccos(1 + 1.0*I)
0.904556894302381 - 1.06127506190504*I
sage: arccos(3/4).n(100)
0.72273424781341561117837735264
We can delay evaluation using the ``hold`` parameter::
sage: arccos(0,hold=True)
arccos(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = arccos(0,hold=True); a.simplify()
1/2*pi
``conjugate(arccos(x))==arccos(conjugate(x))``, unless on the branch
cuts, which run along the real axis outside the interval [-1, +1].::
sage: conjugate(arccos(x))
conjugate(arccos(x))
sage: var('y', domain='positive')
y
sage: conjugate(arccos(y))
conjugate(arccos(y))
sage: conjugate(arccos(y+I))
conjugate(arccos(y + I))
sage: conjugate(arccos(1/16))
arccos(1/16)
sage: conjugate(arccos(2))
conjugate(arccos(2))
sage: conjugate(arccos(-2))
pi - conjugate(arccos(2))
TESTS::
sage: arccos(x)._sympy_()
acos(x)
sage: arccos(x).operator()
arccos
sage: acos(complex(1,1))
(0.9045568943023814-1.0612750619050357j)
sage: acos(SR(2.1))
1.37285914424258*I
"""
GinacFunction.__init__(self,
'arccos',
latex_name=r"\arccos",
conversions=dict(maxima='acos',
sympy='acos',
mathematica='ArcCos',
fricas='acos',
giac='acos'))
def __init__(self):
r"""
The polylog function
`\text{Li}_s(z) = \sum_{k=1}^{\infty} z^k / k^s`.
This definition is valid for arbitrary complex order `s` and for
all complex arguments `z` with `|z| < 1`; it can be extended to
`|z| \ge 1` by the process of analytic continuation. So the
function may have a discontinuity at `z=1` which can cause a
`NaN` value returned for floating point arguments.
EXAMPLES::
sage: polylog(2.7, 0)
0
sage: polylog(2, 1)
1/6*pi^2
sage: polylog(2, -1)
-1/12*pi^2
sage: polylog(3, -1)
-3/4*zeta(3)
sage: polylog(2, I)
I*catalan - 1/48*pi^2
sage: polylog(4, 1/2)
polylog(4, 1/2)
sage: polylog(4, 0.5)
0.517479061673899
sage: polylog(1, x)
-log(-x + 1)
sage: polylog(2,x^2+1)
dilog(x^2 + 1)
sage: f = polylog(4, 1); f
1/90*pi^4
sage: f.n()
1.08232323371114
sage: polylog(4, 2).n()
2.42786280675470 - 0.174371300025453*I
sage: complex(polylog(4,2))
(2.4278628067547032-0.17437130002545306j)
sage: float(polylog(4,0.5))
0.5174790616738993
sage: z = var('z')
sage: polylog(2,z).series(z==0, 5)
1*z + 1/4*z^2 + 1/9*z^3 + 1/16*z^4 + Order(z^5)
sage: loads(dumps(polylog))
polylog
sage: latex(polylog(5, x))
{\rm Li}_{5}(x)
sage: polylog(x, x)._sympy_()
polylog(x, x)
TESTS:
Check if :trac:`8459` is fixed::
sage: t = maxima(polylog(5,x)).sage(); t
polylog(5, x)
sage: t.operator() == polylog
True
sage: t.subs(x=.5).n()
0.50840057924226...
Check if :trac:`18386` is fixed::
sage: polylog(2.0, 1)
1.64493406684823
sage: polylog(2, 1.0)
NaN
sage: polylog(2.0, 1.0)
NaN
"""
GinacFunction.__init__(self, "polylog", nargs=2)
def __init__(self):
"""
The arcsine function.
EXAMPLES::
sage: arcsin(0.5)
0.523598775598299
sage: arcsin(1/2)
1/6*pi
sage: arcsin(1 + 1.0*I)
0.666239432492515 + 1.06127506190504*I
We can delay evaluation using the ``hold`` parameter::
sage: arcsin(0,hold=True)
arcsin(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = arcsin(0,hold=True); a.simplify()
0
``conjugate(arcsin(x))==arcsin(conjugate(x))``, unless on the branch
cuts which run along the real axis outside the interval [-1, +1].::
sage: conjugate(arcsin(x))
conjugate(arcsin(x))
sage: var('y', domain='positive')
y
sage: conjugate(arcsin(y))
conjugate(arcsin(y))
sage: conjugate(arcsin(y+I))
conjugate(arcsin(y + I))
sage: conjugate(arcsin(1/16))
arcsin(1/16)
sage: conjugate(arcsin(2))
conjugate(arcsin(2))
sage: conjugate(arcsin(-2))
-conjugate(arcsin(2))
TESTS::
sage: arcsin(x)._sympy_()
asin(x)
sage: arcsin(x).operator()
arcsin
sage: asin(complex(1,1))
(0.6662394324925152+1.0612750619050357j)
sage: asin(SR(2.1))
1.57079632679490 - 1.37285914424258*I
"""
GinacFunction.__init__(self,
'arcsin',
latex_name=r"\arcsin",
conversions=dict(maxima='asin',
sympy='asin',
mathematica='ArcSin',
fricas="asin",
giac="asin"))
def __init__(self):
r"""
Returns the factorial of `n`.
INPUT:
- ``n`` - any complex argument (except negative
integers) or any symbolic expression
OUTPUT: an integer or symbolic expression
EXAMPLES::
sage: x = var('x')
sage: factorial(0)
1
sage: factorial(4)
24
sage: factorial(10)
3628800
sage: factorial(6) == 6*5*4*3*2
True
sage: f = factorial(x + factorial(x)); f
factorial(x + factorial(x))
sage: f(x=3)
362880
sage: factorial(x)^2
factorial(x)^2
To prevent automatic evaluation use the ``hold`` argument::
sage: factorial(5,hold=True)
factorial(5)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: factorial(5,hold=True).simplify()
120
We can also give input other than nonnegative integers. For
other nonnegative numbers, the :func:`gamma` function is used::
sage: factorial(1/2)
1/2*sqrt(pi)
sage: factorial(3/4)
gamma(7/4)
sage: factorial(2.3)
2.68343738195577
But negative input always fails::
sage: factorial(-32)
Traceback (most recent call last):
...
ValueError: factorial -- self = (-32) must be nonnegative
TESTS:
We verify that we can convert this function to Maxima and
bring it back into Sage.::
sage: z = var('z')
sage: factorial._maxima_init_()
'factorial'
sage: maxima(factorial(z))
z!
sage: _.sage()
factorial(z)
sage: k = var('k')
sage: factorial(k)
factorial(k)
sage: factorial(3.14)
7.173269190187...
Test latex typesetting::
sage: latex(factorial(x))
x!
sage: latex(factorial(2*x))
\left(2 \, x\right)!
sage: latex(factorial(sin(x)))
\sin\left(x\right)!
sage: latex(factorial(sqrt(x+1)))
\left(\sqrt{x + 1}\right)!
sage: latex(factorial(sqrt(x)))
\sqrt{x}!
sage: latex(factorial(x^(2/3)))
\left(x^{\frac{2}{3}}\right)!
sage: latex(factorial)
{\rm factorial}
"""
GinacFunction.__init__(self,
"factorial",
latex_name='{\\rm factorial}',
conversions=dict(maxima='factorial',
mathematica='Factorial'))
def __init__(self):
r"""
The cosine function.
EXAMPLES::
sage: cos(pi)
-1
sage: cos(x).subs(x==pi)
-1
sage: cos(2).n(100)
-0.41614683654714238699756822950
sage: loads(dumps(cos))
cos
sage: cos(x)._sympy_()
cos(x)
We can prevent evaluation using the ``hold`` parameter::
sage: cos(0,hold=True)
cos(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = cos(0,hold=True); a.simplify()
1
If possible, the argument is also reduced modulo the
period length `2\pi`, and well-known identities are
directly evaluated::
sage: k = var('k', domain='integer')
sage: cos(1 + 2*k*pi)
cos(1)
sage: cos(k*pi)
cos(pi*k)
sage: cos(pi/3 + 2*k*pi)
1/2
TESTS::
sage: conjugate(cos(x))
cos(conjugate(x))
sage: cos(complex(1,1)) # rel tol 1e-15
(0.8337300251311491-0.9888977057628651j)
Check that :trac:`20752` is fixed::
sage: cos(3*pi+41/42*pi)
cos(1/42*pi)
sage: cos(-5*pi+1/42*pi)
-cos(1/42*pi)
sage: cos(pi-1/42*pi)
-cos(1/42*pi)
"""
GinacFunction.__init__(self,
'cos',
latex_name=r"\cos",
conversions=dict(maxima='cos',
mathematica='Cos',
giac='cos',
fricas='cos',
sympy='cos'))
def __init__(self):
r"""
The dilogarithm function
`\text{Li}_2(z) = \sum_{k=1}^{\infty} z^k / k^2`.
This is simply an alias for polylog(2, z).
EXAMPLES::
sage: dilog(1)
1/6*pi^2
sage: dilog(1/2)
1/12*pi^2 - 1/2*log(2)^2
sage: dilog(x^2+1)
dilog(x^2 + 1)
sage: dilog(-1)
-1/12*pi^2
sage: dilog(-1.0)
-0.822467033424113
sage: dilog(-1.1)
-0.890838090262283
sage: dilog(1/2)
1/12*pi^2 - 1/2*log(2)^2
sage: dilog(.5)
0.582240526465012
sage: dilog(1/2).n()
0.582240526465012
sage: var('z')
z
sage: dilog(z).diff(z, 2)
log(-z + 1)/z^2 - 1/((z - 1)*z)
sage: dilog(z).series(z==1/2, 3)
(1/12*pi^2 - 1/2*log(2)^2) + (-2*log(1/2))*(z - 1/2) + (2*log(1/2) + 2)*(z - 1/2)^2 + Order(1/8*(2*z - 1)^3)
sage: latex(dilog(z))
{\rm Li}_2\left(z\right)
Dilog has a branch point at `1`. Sage's floating point libraries
may handle this differently from the symbolic package::
sage: dilog(1)
1/6*pi^2
sage: dilog(1.)
1.64493406684823
sage: dilog(1).n()
1.64493406684823
sage: float(dilog(1))
1.6449340668482262
TESTS:
``conjugate(dilog(x))==dilog(conjugate(x))`` unless on the branch cuts
which run along the positive real axis beginning at 1.::
sage: conjugate(dilog(x))
conjugate(dilog(x))
sage: var('y',domain='positive')
y
sage: conjugate(dilog(y))
conjugate(dilog(y))
sage: conjugate(dilog(1/19))
dilog(1/19)
sage: conjugate(dilog(1/2*I))
dilog(-1/2*I)
sage: dilog(conjugate(1/2*I))
dilog(-1/2*I)
sage: conjugate(dilog(2))
conjugate(dilog(2))
Check that return type matches argument type where possible
(:trac:`18386`)::
sage: dilog(0.5)
0.582240526465012
sage: dilog(-1.0)
-0.822467033424113
sage: y = dilog(RealField(13)(0.5))
sage: parent(y)
Real Field with 13 bits of precision
sage: dilog(RealField(13)(1.1))
1.96 - 0.300*I
sage: parent(_)
Complex Field with 13 bits of precision
"""
GinacFunction.__init__(self,
'dilog',
conversions=dict(maxima='li[2]',
magma='Dilog',
fricas='(x+->dilog(1-x))'))
def __init__(self):
r"""
The polylog function
`\text{Li}_s(z) = \sum_{k=1}^{\infty} z^k / k^s`.
The first argument is `s` (usually an integer called the weight)
and the second argument is `z` : ``polylog(s, z)``.
This definition is valid for arbitrary complex numbers `s` and `z`
with `|z| < 1`. It can be extended to `|z| \ge 1` by the process of
analytic continuation, with a branch cut along the positive real axis
from `1` to `+\infty`. A `NaN` value may be returned for floating
point arguments that are on the branch cut.
EXAMPLES::
sage: polylog(2.7, 0)
0.000000000000000
sage: polylog(2, 1)
1/6*pi^2
sage: polylog(2, -1)
-1/12*pi^2
sage: polylog(3, -1)
-3/4*zeta(3)
sage: polylog(2, I)
I*catalan - 1/48*pi^2
sage: polylog(4, 1/2)
polylog(4, 1/2)
sage: polylog(4, 0.5)
0.517479061673899
sage: polylog(1, x)
-log(-x + 1)
sage: polylog(2,x^2+1)
dilog(x^2 + 1)
sage: f = polylog(4, 1); f
1/90*pi^4
sage: f.n()
1.08232323371114
sage: polylog(4, 2).n()
2.42786280675470 - 0.174371300025453*I
sage: complex(polylog(4,2))
(2.4278628067547032-0.17437130002545306j)
sage: float(polylog(4,0.5))
0.5174790616738993
sage: z = var('z')
sage: polylog(2,z).series(z==0, 5)
1*z + 1/4*z^2 + 1/9*z^3 + 1/16*z^4 + Order(z^5)
sage: loads(dumps(polylog))
polylog
sage: latex(polylog(5, x))
{\rm Li}_{5}(x)
sage: polylog(x, x)._sympy_()
polylog(x, x)
TESTS:
Check if :trac:`8459` is fixed::
sage: t = maxima(polylog(5,x)).sage(); t
polylog(5, x)
sage: t.operator() == polylog
True
sage: t.subs(x=.5).n()
0.50840057924226...
Check if :trac:`18386` is fixed::
sage: polylog(2.0, 1)
1.64493406684823
sage: polylog(2, 1.0)
1.64493406684823
sage: polylog(2.0, 1.0)
1.64493406684823
sage: polylog(2, RealBallField(100)(1/3))
[0.36621322997706348761674629766... +/- ...]
sage: polylog(2, ComplexBallField(100)(4/3))
[2.27001825336107090380391448586 +/- ...] + [-0.90377988538400159956755721265 +/- ...]*I
sage: polylog(2, CBF(1/3))
[0.366213229977063 +/- ...]
sage: parent(_)
Complex ball field with 53 bits of precision
sage: polylog(2, CBF(1))
[1.644934066848226 +/- ...]
sage: parent(_)
Complex ball field with 53 bits of precision
sage: polylog(1,-1) # known bug
-log(2)
Check for :trac:`21907`::
sage: bool(x*polylog(x,x)==0)
False
"""
GinacFunction.__init__(self,
"polylog",
nargs=2,
conversions=dict(mathematica='PolyLog',
magma='Polylog',
matlab='polylog',
sympy='polylog'))
def __init__(self):
r"""
The exponential function, `\exp(x) = e^x`.
EXAMPLES::
sage: exp(-1)
e^(-1)
sage: exp(2)
e^2
sage: exp(2).n(100)
7.3890560989306502272304274606
sage: exp(x^2 + log(x))
e^(x^2 + log(x))
sage: exp(x^2 + log(x)).simplify()
x*e^(x^2)
sage: exp(2.5)
12.1824939607035
sage: exp(float(2.5))
12.182493960703473
sage: exp(RDF('2.5'))
12.1824939607
To prevent automatic evaluation, use the ``hold`` parameter::
sage: exp(I*pi,hold=True)
e^(I*pi)
sage: exp(0,hold=True)
e^0
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: exp(0,hold=True).simplify()
1
::
sage: exp(pi*I/2)
I
sage: exp(pi*I)
-1
sage: exp(8*pi*I)
1
sage: exp(7*pi*I/2)
-I
TEST::
sage: latex(exp(x))
e^{x}
sage: latex(exp(sqrt(x)))
e^{\sqrt{x}}
sage: latex(exp)
\exp
sage: latex(exp(sqrt(x))^x)
\left(e^{\sqrt{x}}\right)^{x}
sage: latex(exp(sqrt(x)^x))
e^{\left(\sqrt{x}^{x}\right)}
Test conjugates::
sage: conjugate(exp(x))
e^conjugate(x)
Test simplifications when taking powers of exp, #7264::
sage: var('a,b,c,II')
(a, b, c, II)
sage: model_exp = exp(II)**a*(b)
sage: sol1_l={b: 5.0, a: 1.1}
sage: model_exp.subs(sol1_l)
5.00000000000000*(e^II)^1.10000000000000
::
sage: exp(3)^II*exp(x)
(e^3)^II*e^x
sage: exp(x)*exp(x)
e^(2*x)
sage: exp(x)*exp(a)
e^(a + x)
sage: exp(x)*exp(a)^2
e^(2*a + x)
Another instance of the same problem, #7394::
sage: 2*sqrt(e)
2*sqrt(e)
"""
GinacFunction.__init__(self,
"exp",
latex_name=r"\exp",
conversions=dict(maxima='exp'))
def __init__(self):
r"""
The Gamma function. This is defined by
`\Gamma(z) = \int_0^\infty t^{z-1}e^{-t} dt`
for complex input `z` with real part greater than zero, and by
analytic continuation on the rest of the complex plane (except
for negative integers, which are poles).
It is computed by various libraries within Sage, depending on
the input type.
EXAMPLES::
sage: from sage.functions.other import gamma1
sage: gamma1(CDF(0.5,14))
-4.05370307804e-10 - 5.77329983455e-10*I
sage: gamma1(CDF(I))
-0.154949828302 - 0.498015668118*I
Recall that `\Gamma(n)` is `n-1` factorial::
sage: gamma1(11) == factorial(10)
True
sage: gamma1(6)
120
sage: gamma1(1/2)
sqrt(pi)
sage: gamma1(-1)
Infinity
sage: gamma1(I)
gamma(I)
sage: gamma1(x/2)(x=5)
3/4*sqrt(pi)
sage: gamma1(float(6))
120.0
sage: gamma1(x)
gamma(x)
::
sage: gamma1(pi)
gamma(pi)
sage: gamma1(i)
gamma(I)
sage: gamma1(i).n()
-0.154949828301811 - 0.498015668118356*I
sage: gamma1(int(5))
24
::
sage: conjugate(gamma(x))
gamma(conjugate(x))
::
sage: plot(gamma1(x),(x,1,5))
To prevent automatic evaluation use the ``hold`` argument::
sage: gamma1(1/2,hold=True)
gamma(1/2)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: gamma1(1/2,hold=True).simplify()
sqrt(pi)
TESTS:
We verify that we can convert this function to Maxima and
convert back to Sage::
sage: z = var('z')
sage: maxima(gamma1(z)).sage()
gamma(z)
sage: latex(gamma1(z))
\Gamma\left(z\right)
Test that Trac ticket 5556 is fixed::
sage: gamma1(3/4)
gamma(3/4)
sage: gamma1(3/4).n(100)
1.2254167024651776451290983034
Check that negative integer input works::
sage: (-1).gamma()
Infinity
sage: (-1.).gamma()
NaN
sage: CC(-1).gamma()
Infinity
sage: RDF(-1).gamma()
NaN
sage: CDF(-1).gamma()
Infinity
Check if #8297 is fixed::
sage: latex(gamma(1/4))
\Gamma\left(\frac{1}{4}\right)
"""
GinacFunction.__init__(self,
"gamma",
latex_name=r'\Gamma',
ginac_name='tgamma',
conversions={
'mathematica': 'Gamma',
'maple': 'GAMMA'
})
def __init__(self):
"""
The arctangent function.
EXAMPLES::
sage: arctan(1/2)
arctan(1/2)
sage: RDF(arctan(1/2)) # rel tol 1e-15
0.46364760900080615
sage: arctan(1 + I)
arctan(I + 1)
sage: arctan(1/2).n(100)
0.46364760900080611621425623146
We can delay evaluation using the ``hold`` parameter::
sage: arctan(0,hold=True)
arctan(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = arctan(0,hold=True); a.simplify()
0
``conjugate(arctan(x))==arctan(conjugate(x))``, unless on the branch
cuts which run along the imaginary axis outside the interval [-I, +I].::
sage: conjugate(arctan(x))
conjugate(arctan(x))
sage: var('y', domain='positive')
y
sage: conjugate(arctan(y))
arctan(y)
sage: conjugate(arctan(y+I))
conjugate(arctan(y + I))
sage: conjugate(arctan(1/16))
arctan(1/16)
sage: conjugate(arctan(-2*I))
conjugate(arctan(-2*I))
sage: conjugate(arctan(2*I))
conjugate(arctan(2*I))
sage: conjugate(arctan(I/2))
arctan(-1/2*I)
TESTS::
sage: arctan(x)._sympy_()
atan(x)
sage: arctan(x).operator()
arctan
sage: atan(complex(1,1))
(1.0172219678978514+0.4023594781085251j)
Check that :trac:`19918` is fixed::
sage: arctan(-x).subs(x=oo)
-1/2*pi
sage: arctan(-x).subs(x=-oo)
1/2*pi
"""
GinacFunction.__init__(self,
'arctan',
latex_name=r"\arctan",
conversions=dict(maxima='atan',
sympy='atan',
mathematica='ArcTan',
fricas='atan',
giac='atan'))
def __init__(self):
r"""
Return the binomial coefficient
.. math::
\binom{x}{m} = x (x-1) \cdots (x-m+1) / m!
which is defined for `m \in \ZZ` and any
`x`. We extend this definition to include cases when
`x-m` is an integer but `m` is not by
.. math::
\binom{x}{m}= \binom{x}{x-m}
If `m < 0`, return `0`.
INPUT:
- ``x``, ``m`` - numbers or symbolic expressions. Either ``m``
or ``x-m`` must be an integer, else the output is symbolic.
OUTPUT: number or symbolic expression (if input is symbolic)
EXAMPLES::
sage: binomial(5,2)
10
sage: binomial(2,0)
1
sage: binomial(1/2, 0)
1
sage: binomial(3,-1)
0
sage: binomial(20,10)
184756
sage: binomial(-2, 5)
-6
sage: binomial(RealField()('2.5'), 2)
1.87500000000000
sage: n=var('n'); binomial(n,2)
1/2*(n - 1)*n
sage: n=var('n'); binomial(n,n)
1
sage: n=var('n'); binomial(n,n-1)
n
sage: binomial(2^100, 2^100)
1
::
sage: k, i = var('k,i')
sage: binomial(k,i)
binomial(k, i)
We can use a ``hold`` parameter to prevent automatic evaluation,
but only using method notation::
sage: SR(5).binomial(3, hold=True)
binomial(5, 3)
sage: SR(5).binomial(3, hold=True).simplify()
10
TESTS: We verify that we can convert this function to Maxima and
bring it back into Sage.
::
sage: n,k = var('n,k')
sage: maxima(binomial(n,k))
binomial(n,k)
sage: _.sage()
binomial(n, k)
sage: sage.functions.other.binomial._maxima_init_() # temporary workaround until we can get symbolic binomial to import in global namespace, if that's desired
'binomial'
"""
GinacFunction.__init__(self,
"binomial",
nargs=2,
conversions=dict(maxima='binomial',
mathematica='Binomial'))
def __init__(self):
r"""
The natural logarithm of x. See `log?` for
more information about its behavior.
EXAMPLES::
sage: ln(e^2)
2
sage: ln(2)
log(2)
sage: ln(10)
log(10)
::
sage: ln(RDF(10))
2.30258509299
sage: ln(2.718)
0.999896315728952
sage: ln(2.0)
0.693147180559945
sage: ln(float(-1))
3.141592653589793j
sage: ln(complex(-1))
3.141592653589793j
We do not currently support a ``hold`` parameter in functional
notation::
sage: log(SR(-1),hold=True)
Traceback (most recent call last):
...
TypeError: log() got an unexpected keyword argument 'hold'
This is possible with method notation::
sage: I.log(hold=True)
log(I)
sage: I.log(hold=True).simplify()
1/2*I*pi
TESTS::
sage: latex(x.log())
\log\left(x\right)
sage: latex(log(1/4))
\log\left(\frac{1}{4}\right)
sage: loads(dumps(ln(x)+1))
log(x) + 1
``conjugate(log(x))==log(conjugate(x))`` unless on the branch cut which
runs along the negative real axis.::
sage: conjugate(log(x))
conjugate(log(x))
sage: var('y', domain='positive')
y
sage: conjugate(log(y))
log(y)
sage: conjugate(log(y+I))
conjugate(log(y + I))
sage: conjugate(log(-1))
-I*pi
sage: log(conjugate(-1))
I*pi
Check if float arguments are handled properly.::
sage: from sage.functions.log import function_log as log
sage: log(float(5))
1.6094379124341003
sage: log(float(0))
-inf
sage: log(float(-1))
3.141592653589793j
sage: log(x).subs(x=float(-1))
3.141592653589793j
"""
GinacFunction.__init__(self,
'log',
latex_name=r'\log',
conversions=dict(maxima='log'))
def __init__(self):
r"""
The polylog function
`\text{Li}_s(z) = \sum_{k=1}^{\infty} z^k / k^s`.
This definition is valid for arbitrary complex order `s` and for
all complex arguments `z` with `|z| < 1`; it can be extended to
`|z| \ge 1` by the process of analytic continuation. So the
function may have a discontinuity at `z=1` which can cause a
`NaN` value returned for floating point arguments.
EXAMPLES::
sage: polylog(2.7, 0)
0.000000000000000
sage: polylog(2, 1)
1/6*pi^2
sage: polylog(2, -1)
-1/12*pi^2
sage: polylog(3, -1)
-3/4*zeta(3)
sage: polylog(2, I)
I*catalan - 1/48*pi^2
sage: polylog(4, 1/2)
polylog(4, 1/2)
sage: polylog(4, 0.5)
0.517479061673899
sage: polylog(1, x)
-log(-x + 1)
sage: polylog(2,x^2+1)
dilog(x^2 + 1)
sage: f = polylog(4, 1); f
1/90*pi^4
sage: f.n()
1.08232323371114
sage: polylog(4, 2).n()
2.42786280675470 - 0.174371300025453*I
sage: complex(polylog(4,2))
(2.4278628067547032-0.17437130002545306j)
sage: float(polylog(4,0.5))
0.5174790616738993
sage: z = var('z')
sage: polylog(2,z).series(z==0, 5)
1*z + 1/4*z^2 + 1/9*z^3 + 1/16*z^4 + Order(z^5)
sage: loads(dumps(polylog))
polylog
sage: latex(polylog(5, x))
{\rm Li}_{5}(x)
sage: polylog(x, x)._sympy_()
polylog(x, x)
TESTS:
Check if :trac:`8459` is fixed::
sage: t = maxima(polylog(5,x)).sage(); t
polylog(5, x)
sage: t.operator() == polylog
True
sage: t.subs(x=.5).n()
0.50840057924226...
Check if :trac:`18386` is fixed::
sage: polylog(2.0, 1)
1.64493406684823
sage: polylog(2, 1.0)
1.64493406684823
sage: polylog(2.0, 1.0)
1.64493406684823
sage: BF = RealBallField(100)
sage: polylog(2, BF(1/3))
[0.36621322997706348761674629766... +/- ...]
sage: polylog(2, BF(4/3))
[2.27001825336107090380391448586 +/- 5.64e-30] + [-0.90377988538400159956755721265 +/- 8.39e-30]*I
sage: parent(_)
Complex ball field with 100 bits of precision
sage: polylog(2, CBF(1/3))
[0.366213229977063 +/- ...]
sage: parent(_)
Complex ball field with 53 bits of precision
sage: polylog(2, CBF(1))
[1.644934066848226 +/- ...]
sage: parent(_)
Complex ball field with 53 bits of precision
"""
GinacFunction.__init__(self, "polylog", nargs=2)
def __init__(self):
"""
The modified arctangent function.
Returns the arc tangent (measured in radians) of `y/x`, where
unlike ``arctan(y/x)``, the signs of both ``x`` and ``y`` are
considered. In particular, this function measures the angle
of a ray through the origin and `(x,y)`, with the positive
`x`-axis the zero mark, and with output angle `\theta`
being between `-\pi<\theta<=\pi`.
Hence, ``arctan2(y,x) = arctan(y/x)`` only for `x>0`. One
may consider the usual arctan to measure angles of lines
through the origin, while the modified function measures
rays through the origin.
Note that the `y`-coordinate is by convention the first input.
EXAMPLES:
Note the difference between the two functions::
sage: arctan2(1,-1)
3/4*pi
sage: arctan(1/-1)
-1/4*pi
This is consistent with Python and Maxima::
sage: maxima.atan2(1,-1)
3*%pi/4
sage: math.atan2(1,-1)
2.356194490192345
More examples::
sage: arctan2(1,0)
1/2*pi
sage: arctan2(2,3)
arctan(2/3)
sage: arctan2(-1,-1)
-3/4*pi
Of course we can approximate as well::
sage: arctan2(-1/2,1).n(100)
-0.46364760900080611621425623146
sage: arctan2(2,3).n(100)
0.58800260354756755124561108063
We can delay evaluation using the ``hold`` parameter::
sage: arctan2(-1/2,1,hold=True)
arctan2(-1/2, 1)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: arctan2(-1/2,1,hold=True).simplify()
-arctan(1/2)
The function also works with numpy arrays as input::
sage: import numpy
sage: a = numpy.linspace(1, 3, 3)
sage: b = numpy.linspace(3, 6, 3)
sage: atan2(a, b)
array([ 0.32175055, 0.41822433, 0.46364761])
sage: atan2(1,a)
array([ 0.78539816, 0.46364761, 0.32175055])
sage: atan2(a, 1)
array([ 0.78539816, 1.10714872, 1.24904577])
TESTS::
sage: x,y = var('x,y')
sage: arctan2(y,x).operator()
arctan2
Check if #8565 is fixed::
sage: atan2(-pi,0)
-1/2*pi
Check if #8564 is fixed::
sage: arctan2(x,x)._sympy_()
atan2(x, x)
Check if numerical evaluation works #9913::
sage: arctan2(0, -log(2)).n()
3.14159265358979
Check if atan2(0,0) throws error of :trac:`11423`::
sage: atan2(0,0)
Traceback (most recent call last):
...
RuntimeError: arctan2_eval(): arctan2(0,0) encountered
sage: atan2(0,0,hold=True)
arctan2(0, 0)
sage: atan2(0,0,hold=True).n()
Traceback (most recent call last):
...
ValueError: arctan2(0,0) undefined
"""
GinacFunction.__init__(self,
"arctan2",
nargs=2,
latex_name=r'\arctan',
conversions=dict(maxima='atan2', sympy='atan2'))
def __init__(self):
r"""
The sine function.
EXAMPLES::
sage: sin(0)
0
sage: sin(x).subs(x==0)
0
sage: sin(2).n(100)
0.90929742682568169539601986591
sage: loads(dumps(sin))
sin
sage: sin(x)._sympy_()
sin(x)
We can prevent evaluation using the ``hold`` parameter::
sage: sin(0,hold=True)
sin(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = sin(0,hold=True); a.simplify()
0
If possible, the argument is also reduced modulo the
period length `2\pi`, and well-known identities are
directly evaluated::
sage: k = var('k', domain='integer')
sage: sin(1 + 2*k*pi)
sin(1)
sage: sin(k*pi)
0
TESTS::
sage: conjugate(sin(x))
sin(conjugate(x))
sage: sin(complex(1,1)) # rel tol 1e-15
(1.2984575814159773+0.6349639147847361j)
sage: sin(pi/5)
1/4*sqrt(-2*sqrt(5) + 10)
sage: sin(pi/8)
1/2*sqrt(-sqrt(2) + 2)
sage: sin(pi/24)
1/4*sqrt(-2*sqrt(6) - 2*sqrt(2) + 8)
sage: sin(pi/30)
-1/8*sqrt(5) + 1/4*sqrt(-3/2*sqrt(5) + 15/2) - 1/8
sage: sin(104*pi/105)
sin(1/105*pi)
sage: cos(pi/8)
1/2*sqrt(sqrt(2) + 2)
sage: cos(pi/10)
1/4*sqrt(2*sqrt(5) + 10)
sage: cos(pi/12)
1/4*sqrt(6) + 1/4*sqrt(2)
sage: cos(pi/15)
1/8*sqrt(5) + 1/4*sqrt(3/2*sqrt(5) + 15/2) - 1/8
sage: cos(pi/24)
1/4*sqrt(2*sqrt(6) + 2*sqrt(2) + 8)
sage: cos(104*pi/105)
-cos(1/105*pi)
sage: tan(pi/5)
sqrt(-2*sqrt(5) + 5)
sage: tan(pi/8)
sqrt(2) - 1
sage: tan(pi/10)
1/5*sqrt(-10*sqrt(5) + 25)
sage: tan(pi/16)
-sqrt(2) + sqrt(2*sqrt(2) + 4) - 1
sage: tan(pi/20)
sqrt(5) - sqrt(2*sqrt(5) + 5) + 1
sage: tan(pi/24)
sqrt(6) - sqrt(3) + sqrt(2) - 2
sage: tan(104*pi/105)
-tan(1/105*pi)
sage: cot(104*pi/105)
-cot(1/105*pi)
sage: sec(104*pi/105)
-sec(1/105*pi)
sage: csc(104*pi/105)
csc(1/105*pi)
sage: all(sin(rat*pi).n(200)-sin(rat*pi,hold=True).n(200) < 1e-30 for rat in [1/5,2/5,1/30,7/30,11/30,13/30,1/8,3/8,1/24,5/24,7/24,11/24])
True
sage: all(cos(rat*pi).n(200)-cos(rat*pi,hold=True).n(200) < 1e-30 for rat in [1/10,3/10,1/12,5/12,1/15,2/15,4/15,7/15,1/8,3/8,1/24,5/24,11/24])
True
sage: all(tan(rat*pi).n(200)-tan(rat*pi,hold=True).n(200) < 1e-30 for rat in [1/5,2/5,1/10,3/10,1/20,3/20,7/20,9/20,1/8,3/8,1/16,3/16,5/16,7/16,1/24,5/24,7/24,11/24])
True
Check that :trac:`20456` is fixed::
sage: assume(x>0)
sage: sin(pi*x)
sin(pi*x)
sage: forget()
Check that :trac:`20752` is fixed::
sage: sin(3*pi+41/42*pi)
-sin(1/42*pi)
sage: sin(-5*pi+1/42*pi)
-sin(1/42*pi)
sage: sin(pi-1/42*pi)
sin(1/42*pi)
"""
GinacFunction.__init__(self,
'sin',
latex_name=r"\sin",
conversions=dict(maxima='sin',
mathematica='Sin',
giac='sin',
fricas='sin',
sympy='sin'))
def __init__(self):
"""
The sine function.
EXAMPLES::
sage: sin(0)
0
sage: sin(x).subs(x==0)
0
sage: sin(2).n(100)
0.90929742682568169539601986591
sage: loads(dumps(sin))
sin
We can prevent evaluation using the ``hold`` parameter::
sage: sin(0,hold=True)
sin(0)
To then evaluate again, we currently must use Maxima via
:meth:`sage.symbolic.expression.Expression.simplify`::
sage: a = sin(0,hold=True); a.simplify()
0
TESTS::
sage: conjugate(sin(x))
sin(conjugate(x))
sage: sin(complex(1,1)) # rel tol 1e-15
(1.2984575814159773+0.6349639147847361j)
sage: sin(pi/5)
1/4*sqrt(-2*sqrt(5) + 10)
sage: sin(pi/8)
1/2*sqrt(-sqrt(2) + 2)
sage: sin(pi/24)
1/4*sqrt(-2*sqrt(6) - 2*sqrt(2) + 8)
sage: sin(pi/30)
-1/8*sqrt(5) + 1/4*sqrt(-3/2*sqrt(5) + 15/2) - 1/8
sage: cos(pi/8)
1/2*sqrt(sqrt(2) + 2)
sage: cos(pi/10)
1/2*sqrt(1/2*sqrt(5) + 5/2)
sage: cos(pi/12)
1/12*sqrt(6)*(sqrt(3) + 3)
sage: cos(pi/15)
1/8*sqrt(5) + 1/4*sqrt(3/2*sqrt(5) + 15/2) - 1/8
sage: cos(pi/24)
1/4*sqrt(2*sqrt(6) + 2*sqrt(2) + 8)
sage: tan(pi/5)
sqrt(-2*sqrt(5) + 5)
sage: tan(pi/8)
sqrt(2) - 1
sage: tan(pi/10)
sqrt(-2/5*sqrt(5) + 1)
sage: tan(pi/16)
-sqrt(2) + sqrt(2*sqrt(2) + 4) - 1
sage: tan(pi/20)
sqrt(5) - 1/2*sqrt(8*sqrt(5) + 20) + 1
sage: tan(pi/24)
sqrt(6) - sqrt(3) + sqrt(2) - 2
sage: all(sin(rat*pi).n(200)-sin(rat*pi,hold=True).n(200) < 1e-30 for rat in [1/5,2/5,1/30,7/30,11/30,13/30,1/8,3/8,1/24,5/24,7/24,11/24])
True
sage: all(cos(rat*pi).n(200)-cos(rat*pi,hold=True).n(200) < 1e-30 for rat in [1/10,3/10,1/12,5/12,1/15,2/15,4/15,7/15,1/8,3/8,1/24,5/24,11/24])
True
sage: all(tan(rat*pi).n(200)-tan(rat*pi,hold=True).n(200) < 1e-30 for rat in [1/5,2/5,1/10,3/10,1/20,3/20,7/20,9/20,1/8,3/8,1/16,3/16,5/16,7/16,1/24,5/24,7/24,11/24])
True
"""
GinacFunction.__init__(self, "sin", latex_name=r"\sin",
conversions=dict(maxima='sin',mathematica='Sin'))