def test_E():
assert E(z, 0) == z
assert E(0, m) == 0
assert E(i * pi / 2, m) == i * E(m)
assert E(z, oo) is zoo
assert E(z, -oo) is zoo
assert E(0) == pi / 2
assert E(1) == 1
assert E(oo) == I * oo
assert E(-oo) is oo
assert E(zoo) is zoo
assert E(-z, m) == -E(z, m)
assert E(z, m).diff(z) == sqrt(1 - m * sin(z) ** 2)
assert E(z, m).diff(m) == (E(z, m) - F(z, m)) / (2 * m)
assert E(z).diff(z) == (E(z) - K(z)) / (2 * z)
r = randcplx()
assert td(E(r, m), m)
assert td(E(z, r), z)
assert td(E(z), z)
mi = Symbol("m", real=False)
assert E(z, mi).conjugate() == E(z.conjugate(), mi.conjugate())
assert E(mi).conjugate() == E(mi.conjugate())
mr = Symbol("m", real=True, negative=True)
assert E(z, mr).conjugate() == E(z.conjugate(), mr)
assert E(mr).conjugate() == E(mr)
assert E(z).rewrite(hyper) == (pi / 2) * hyper(
(Rational(-1, 2), S.Half), (S.One,), z
)
assert tn(E(z), (pi / 2) * hyper((Rational(-1, 2), S.Half), (S.One,), z))
assert (
E(z).rewrite(meijerg)
== -meijerg(((S.Half, Rational(3, 2)), []), ((S.Zero,), (S.Zero,)), -z) / 4
)
assert tn(
E(z), -meijerg(((S.Half, Rational(3, 2)), []), ((S.Zero,), (S.Zero,)), -z) / 4
)
assert E(z, m).series(z) == z + z ** 5 * (
-(m ** 2) / 40 + m / 30
) - m * z ** 3 / 6 + O(z ** 6)
assert E(z).series(
z
) == pi / 2 - pi * z / 8 - 3 * pi * z ** 2 / 128 - 5 * pi * z ** 3 / 512 - 175 * pi * z ** 4 / 32768 - 441 * pi * z ** 5 / 131072 + O(
z ** 6
)
assert (
E(z, m)
.rewrite(Integral)
.dummy_eq(Integral(sqrt(1 - m * sin(t) ** 2), (t, 0, z)))
)
assert (
E(m)
.rewrite(Integral)
.dummy_eq(Integral(sqrt(1 - m * sin(t) ** 2), (t, 0, pi / 2)))
)
def test_F():
assert F(z, 0) == z
assert F(0, m) == 0
assert F(pi*i/2, m) == i*K(m)
assert F(z, oo) == 0
assert F(z, -oo) == 0
assert F(-z, m) == -F(z, m)
assert F(z, m).diff(z) == 1/sqrt(1 - m*sin(z)**2)
assert F(z, m).diff(m) == E(z, m)/(2*m*(1 - m)) - F(z, m)/(2*m) - \
sin(2*z)/(4*(1 - m)*sqrt(1 - m*sin(z)**2))
r = randcplx()
assert td(F(z, r), z)
assert td(F(r, m), m)
mi = Symbol('m', real=False)
assert F(z, mi).conjugate() == F(z.conjugate(), mi.conjugate())
mr = Symbol('m', real=True, negative=True)
assert F(z, mr).conjugate() == F(z.conjugate(), mr)
assert F(z, m).series(z) == \
z + z**5*(3*m**2/40 - m/30) + m*z**3/6 + O(z**6)
assert F(z, m).rewrite(Integral).dummy_eq(
Integral(1/sqrt(1 - m*sin(t)**2), (t, 0, z)))
def test_E():
assert E(z, 0) == z
assert E(0, m) == 0
assert E(i * pi / 2, m) == i * E(m)
assert E(z, oo) == zoo
assert E(z, -oo) == zoo
assert E(0) == pi / 2
assert E(1) == 1
assert E(oo) == I * oo
assert E(-oo) == oo
assert E(zoo) == zoo
assert E(-z, m) == -E(z, m)
assert E(z, m).diff(z) == sqrt(1 - m * sin(z)**2)
assert E(z, m).diff(m) == (E(z, m) - F(z, m)) / (2 * m)
assert E(z).diff(z) == (E(z) - K(z)) / (2 * z)
r = randcplx()
assert td(E(r, m), m)
assert td(E(z, r), z)
assert td(E(z), z)
mi = Symbol('m', real=False)
assert E(z, mi).conjugate() == E(z.conjugate(), mi.conjugate())
mr = Symbol('m', real=True, negative=True)
assert E(z, mr).conjugate() == E(z.conjugate(), mr)
assert E(z).rewrite(hyper) == (pi / 2) * hyper((-S.Half, S.Half),
(S.One, ), z)
assert tn(E(z), (pi / 2) * hyper((-S.Half, S.Half), (S.One, ), z))
assert E(z).rewrite(meijerg) == \
-meijerg(((S.Half, S(3)/2), []), ((S.Zero,), (S.Zero,)), -z)/4
assert tn(
E(z), -meijerg(((S.Half, S(3) / 2), []),
((S.Zero, ), (S.Zero, )), -z) / 4)
def test_E():
assert E(z, 0) == z
assert E(0, m) == 0
assert E(i*pi/2, m) == i*E(m)
assert E(z, oo) == zoo
assert E(z, -oo) == zoo
assert E(0) == pi/2
assert E(1) == 1
assert E(oo) == I*oo
assert E(-oo) == oo
assert E(zoo) == zoo
assert E(-z, m) == -E(z, m)
assert E(z, m).diff(z) == sqrt(1 - m*sin(z)**2)
assert E(z, m).diff(m) == (E(z, m) - F(z, m))/(2*m)
assert E(z).diff(z) == (E(z) - K(z))/(2*z)
r = randcplx()
assert td(E(r, m), m)
assert td(E(z, r), z)
assert td(E(z), z)
mi = Symbol('m', real=False)
assert E(z, mi).conjugate() == E(z.conjugate(), mi.conjugate())
mr = Symbol('m', real=True, negative=True)
assert E(z, mr).conjugate() == E(z.conjugate(), mr)
assert E(z).rewrite(hyper) == (pi/2)*hyper((-S.Half, S.Half), (S.One,), z)
assert tn(E(z), (pi/2)*hyper((-S.Half, S.Half), (S.One,), z))
assert E(z).rewrite(meijerg) == \
-meijerg(((S.Half, S(3)/2), []), ((S.Zero,), (S.Zero,)), -z)/4
assert tn(E(z), -meijerg(((S.Half, S(3)/2), []), ((S.Zero,), (S.Zero,)), -z)/4)
def test_P():
assert P(0, z, m) == F(z, m)
assert P(1, z, m) == F(z, m) + \
(sqrt(1 - m*sin(z)**2)*tan(z) - E(z, m))/(1 - m)
assert P(n, i * pi / 2, m) == i * P(n, m)
assert P(n, z, 0) == atanh(sqrt(n - 1) * tan(z)) / sqrt(n - 1)
assert P(n, z,
n) == F(z, n) - P(1, z, n) + tan(z) / sqrt(1 - n * sin(z)**2)
assert P(oo, z, m) == 0
assert P(-oo, z, m) == 0
assert P(n, z, oo) == 0
assert P(n, z, -oo) == 0
assert P(0, m) == K(m)
assert P(1, m) is zoo
assert P(n, 0) == pi / (2 * sqrt(1 - n))
assert P(2, 1) is -oo
assert P(-1, 1) is oo
assert P(n, n) == E(n) / (1 - n)
assert P(n, -z, m) == -P(n, z, m)
ni, mi = Symbol('n', real=False), Symbol('m', real=False)
assert P(ni, z, mi).conjugate() == \
P(ni.conjugate(), z.conjugate(), mi.conjugate())
nr, mr = Symbol('n', real=True, negative=True), \
Symbol('m', real=True, negative=True)
assert P(nr, z, mr).conjugate() == P(nr, z.conjugate(), mr)
assert P(n, m).conjugate() == P(n.conjugate(), m.conjugate())
assert P(n, z, m).diff(n) == (E(z, m) + (m - n) * F(z, m) / n +
(n**2 - m) * P(n, z, m) / n -
n * sqrt(1 - m * sin(z)**2) * sin(2 * z) /
(2 * (1 - n * sin(z)**2))) / (2 * (m - n) *
(n - 1))
assert P(n, z,
m).diff(z) == 1 / (sqrt(1 - m * sin(z)**2) * (1 - n * sin(z)**2))
assert P(
n, z,
m).diff(m) == (E(z, m) / (m - 1) + P(n, z, m) - m * sin(2 * z) /
(2 * (m - 1) * sqrt(1 - m * sin(z)**2))) / (2 * (n - m))
assert P(n,
m).diff(n) == (E(m) + (m - n) * K(m) / n +
(n**2 - m) * P(n, m) / n) / (2 * (m - n) * (n - 1))
assert P(n, m).diff(m) == (E(m) / (m - 1) + P(n, m)) / (2 * (n - m))
rx, ry = randcplx(), randcplx()
assert td(P(n, rx, ry), n)
assert td(P(rx, z, ry), z)
assert td(P(rx, ry, m), m)
assert P(n, z, m).series(z) == z + z**3*(m/6 + n/3) + \
z**5*(3*m**2/40 + m*n/10 - m/30 + n**2/5 - n/15) + O(z**6)
assert P(n, z, m).rewrite(Integral).dummy_eq(
Integral(1 / ((1 - n * sin(t)**2) * sqrt(1 - m * sin(t)**2)),
(t, 0, z)))
assert P(n, m).rewrite(Integral).dummy_eq(
Integral(1 / ((1 - n * sin(t)**2) * sqrt(1 - m * sin(t)**2)),
(t, 0, pi / 2)))
def test_P():
assert P(0, z, m) == F(z, m)
assert P(1, z, m) == F(z, m) + \
(sqrt(1 - m*sin(z)**2)*tan(z) - E(z, m))/(1 - m)
assert P(n, i*pi/2, m) == i*P(n, m)
assert P(n, z, 0) == atanh(sqrt(n - 1)*tan(z))/sqrt(n - 1)
assert P(n, z, n) == F(z, n) - P(1, z, n) + tan(z)/sqrt(1 - n*sin(z)**2)
assert P(oo, z, m) == 0
assert P(-oo, z, m) == 0
assert P(n, z, oo) == 0
assert P(n, z, -oo) == 0
assert P(0, m) == K(m)
assert P(1, m) is zoo
assert P(n, 0) == pi/(2*sqrt(1 - n))
assert P(2, 1) is -oo
assert P(-1, 1) is oo
assert P(n, n) == E(n)/(1 - n)
assert P(n, -z, m) == -P(n, z, m)
ni, mi = Symbol('n', real=False), Symbol('m', real=False)
assert P(ni, z, mi).conjugate() == \
P(ni.conjugate(), z.conjugate(), mi.conjugate())
nr, mr = Symbol('n', real=True, negative=True), \
Symbol('m', real=True, negative=True)
assert P(nr, z, mr).conjugate() == P(nr, z.conjugate(), mr)
assert P(n, m).conjugate() == P(n.conjugate(), m.conjugate())
assert P(n, z, m).diff(n) == (E(z, m) + (m - n)*F(z, m)/n +
(n**2 - m)*P(n, z, m)/n - n*sqrt(1 -
m*sin(z)**2)*sin(2*z)/(2*(1 - n*sin(z)**2)))/(2*(m - n)*(n - 1))
assert P(n, z, m).diff(z) == 1/(sqrt(1 - m*sin(z)**2)*(1 - n*sin(z)**2))
assert P(n, z, m).diff(m) == (E(z, m)/(m - 1) + P(n, z, m) -
m*sin(2*z)/(2*(m - 1)*sqrt(1 - m*sin(z)**2)))/(2*(n - m))
assert P(n, m).diff(n) == (E(m) + (m - n)*K(m)/n +
(n**2 - m)*P(n, m)/n)/(2*(m - n)*(n - 1))
assert P(n, m).diff(m) == (E(m)/(m - 1) + P(n, m))/(2*(n - m))
# These tests fail due to
# https://github.com/fredrik-johansson/mpmath/issues/571#issuecomment-777201962
# https://github.com/sympy/sympy/issues/20933#issuecomment-777080385
#
# rx, ry = randcplx(), randcplx()
# assert td(P(n, rx, ry), n)
# assert td(P(rx, z, ry), z)
# assert td(P(rx, ry, m), m)
assert P(n, z, m).series(z) == z + z**3*(m/6 + n/3) + \
z**5*(3*m**2/40 + m*n/10 - m/30 + n**2/5 - n/15) + O(z**6)
assert P(n, z, m).rewrite(Integral).dummy_eq(
Integral(1/((1 - n*sin(t)**2)*sqrt(1 - m*sin(t)**2)), (t, 0, z)))
assert P(n, m).rewrite(Integral).dummy_eq(
Integral(1/((1 - n*sin(t)**2)*sqrt(1 - m*sin(t)**2)), (t, 0, pi/2)))
def test_P():
assert P(0, z, m) == F(z, m)
assert P(1, z, m) == F(z, m) + \
(sqrt(1 - m*sin(z)**2)*tan(z) - E(z, m))/(1 - m)
assert P(n, i * pi / 2, m) == i * P(n, m)
assert P(n, z, 0) == atanh(sqrt(n - 1) * tan(z)) / sqrt(n - 1)
assert P(n, z,
n) == F(z, n) - P(1, z, n) + tan(z) / sqrt(1 - n * sin(z)**2)
assert P(oo, z, m) == 0
assert P(-oo, z, m) == 0
assert P(n, z, oo) == 0
assert P(n, z, -oo) == 0
assert P(0, m) == K(m)
assert P(1, m) == zoo
assert P(n, 0) == pi / (2 * sqrt(1 - n))
assert P(2, 1) == -oo
assert P(-1, 1) == oo
assert P(n, n) == E(n) / (1 - n)
assert P(n, -z, m) == -P(n, z, m)
ni, mi = Symbol('n', real=False), Symbol('m', real=False)
assert P(ni, z, mi).conjugate() == \
P(ni.conjugate(), z.conjugate(), mi.conjugate())
nr, mr = Symbol('n', real=True, negative=True), \
Symbol('m', real=True, negative=True)
assert P(nr, z, mr).conjugate() == P(nr, z.conjugate(), mr)
assert P(n, m).conjugate() == P(n.conjugate(), m.conjugate())
assert P(n, z, m).diff(n) == (E(z, m) + (m - n) * F(z, m) / n +
(n**2 - m) * P(n, z, m) / n -
n * sqrt(1 - m * sin(z)**2) * sin(2 * z) /
(2 * (1 - n * sin(z)**2))) / (2 * (m - n) *
(n - 1))
assert P(n, z,
m).diff(z) == 1 / (sqrt(1 - m * sin(z)**2) * (1 - n * sin(z)**2))
assert P(
n, z,
m).diff(m) == (E(z, m) / (m - 1) + P(n, z, m) - m * sin(2 * z) /
(2 * (m - 1) * sqrt(1 - m * sin(z)**2))) / (2 * (n - m))
assert P(n,
m).diff(n) == (E(m) + (m - n) * K(m) / n +
(n**2 - m) * P(n, m) / n) / (2 * (m - n) * (n - 1))
assert P(n, m).diff(m) == (E(m) / (m - 1) + P(n, m)) / (2 * (n - m))
rx, ry = randcplx(), randcplx()
assert td(P(n, rx, ry), n)
assert td(P(rx, z, ry), z)
assert td(P(rx, ry, m), m)
def test_P():
assert P(0, z, m) == F(z, m)
assert P(1, z, m) == F(z, m) + (sqrt(1 - m * sin(z) ** 2) * tan(z) - E(z, m)) / (1 - m)
assert P(n, i * pi / 2, m) == i * P(n, m)
assert P(n, z, 0) == atanh(sqrt(n - 1) * tan(z)) / sqrt(n - 1)
assert P(n, z, n) == F(z, n) - P(1, z, n) + tan(z) / sqrt(1 - n * sin(z) ** 2)
assert P(oo, z, m) == 0
assert P(-oo, z, m) == 0
assert P(n, z, oo) == 0
assert P(n, z, -oo) == 0
assert P(0, m) == K(m)
assert P(1, m) == zoo
assert P(n, 0) == pi / (2 * sqrt(1 - n))
assert P(2, 1) == -oo
assert P(-1, 1) == oo
assert P(n, n) == E(n) / (1 - n)
assert P(n, -z, m) == -P(n, z, m)
ni, mi = Symbol("n", real=False), Symbol("m", real=False)
assert P(ni, z, mi).conjugate() == P(ni.conjugate(), z.conjugate(), mi.conjugate())
nr, mr = Symbol("n", real=True, negative=True), Symbol("m", real=True, negative=True)
assert P(nr, z, mr).conjugate() == P(nr, z.conjugate(), mr)
assert P(n, m).conjugate() == P(n.conjugate(), m.conjugate())
assert P(n, z, m).diff(n) == (
E(z, m)
+ (m - n) * F(z, m) / n
+ (n ** 2 - m) * P(n, z, m) / n
- n * sqrt(1 - m * sin(z) ** 2) * sin(2 * z) / (2 * (1 - n * sin(z) ** 2))
) / (2 * (m - n) * (n - 1))
assert P(n, z, m).diff(z) == 1 / (sqrt(1 - m * sin(z) ** 2) * (1 - n * sin(z) ** 2))
assert P(n, z, m).diff(m) == (
E(z, m) / (m - 1) + P(n, z, m) - m * sin(2 * z) / (2 * (m - 1) * sqrt(1 - m * sin(z) ** 2))
) / (2 * (n - m))
assert P(n, m).diff(n) == (E(m) + (m - n) * K(m) / n + (n ** 2 - m) * P(n, m) / n) / (2 * (m - n) * (n - 1))
assert P(n, m).diff(m) == (E(m) / (m - 1) + P(n, m)) / (2 * (n - m))
rx, ry = randcplx(), randcplx()
assert td(P(n, rx, ry), n)
assert td(P(rx, z, ry), z)
assert td(P(rx, ry, m), m)
assert P(n, z, m).series(z) == z + z ** 3 * (m / 6 + n / 3) + z ** 5 * (
3 * m ** 2 / 40 + m * n / 10 - m / 30 + n ** 2 / 5 - n / 15
) + O(z ** 6)
def test_E():
assert E(z, 0) == z
assert E(0, m) == 0
assert E(i * pi / 2, m) == i * E(m)
assert E(z, oo) == zoo
assert E(z, -oo) == zoo
assert E(0) == pi / 2
assert E(1) == 1
assert E(oo) == I * oo
assert E(-oo) == oo
assert E(zoo) == zoo
assert E(-z, m) == -E(z, m)
assert E(z, m).diff(z) == sqrt(1 - m * sin(z)**2)
assert E(z, m).diff(m) == (E(z, m) - F(z, m)) / (2 * m)
assert E(z).diff(z) == (E(z) - K(z)) / (2 * z)
r = randcplx()
assert td(E(r, m), m)
assert td(E(z, r), z)
assert td(E(z), z)
mi = Symbol('m', real=False)
assert E(z, mi).conjugate() == E(z.conjugate(), mi.conjugate())
assert E(mi).conjugate() == E(mi.conjugate())
mr = Symbol('m', real=True, negative=True)
assert E(z, mr).conjugate() == E(z.conjugate(), mr)
assert E(mr).conjugate() == E(mr)
assert E(z).rewrite(hyper) == (pi / 2) * hyper((-S.Half, S.Half),
(S.One, ), z)
assert tn(E(z), (pi / 2) * hyper((-S.Half, S.Half), (S.One, ), z))
assert E(z).rewrite(meijerg) == \
-meijerg(((S.Half, S(3)/2), []), ((S.Zero,), (S.Zero,)), -z)/4
assert tn(
E(z), -meijerg(((S.Half, S(3) / 2), []),
((S.Zero, ), (S.Zero, )), -z) / 4)
assert E(z, m).series(z) == \
z + z**5*(-m**2/40 + m/30) - m*z**3/6 + O(z**6)
assert E(z).series(z) == pi/2 - pi*z/8 - 3*pi*z**2/128 - \
5*pi*z**3/512 - 175*pi*z**4/32768 - 441*pi*z**5/131072 + O(z**6)
def test_F():
assert F(z, 0) == z
assert F(0, m) == 0
assert F(pi * i / 2, m) == i * K(m)
assert F(z, oo) == 0
assert F(z, -oo) == 0
assert F(-z, m) == -F(z, m)
assert F(z, m).diff(z) == 1 / sqrt(1 - m * sin(z)**2)
assert F(z, m).diff(m) == E(z, m)/(2*m*(1 - m)) - F(z, m)/(2*m) - \
sin(2*z)/(4*(1 - m)*sqrt(1 - m*sin(z)**2))
r = randcplx()
assert td(F(z, r), z)
assert td(F(r, m), m)
mi = Symbol('m', real=False)
assert F(z, mi).conjugate() == F(z.conjugate(), mi.conjugate())
mr = Symbol('m', real=True, negative=True)
assert F(z, mr).conjugate() == F(z.conjugate(), mr)
def test_F():
assert F(z, 0) == z
assert F(0, m) == 0
assert F(pi*i/2, m) == i*K(m)
assert F(z, oo) == 0
assert F(z, -oo) == 0
assert F(-z, m) == -F(z, m)
assert F(z, m).diff(z) == 1/sqrt(1 - m*sin(z)**2)
assert F(z, m).diff(m) == E(z, m)/(2*m*(1 - m)) - F(z, m)/(2*m) - \
sin(2*z)/(4*(1 - m)*sqrt(1 - m*sin(z)**2))
r = randcplx()
assert td(F(z, r), z)
assert td(F(r, m), m)
mi = Symbol('m', real=False)
assert F(z, mi).conjugate() == F(z.conjugate(), mi.conjugate())
mr = Symbol('m', real=True, negative=True)
assert F(z, mr).conjugate() == F(z.conjugate(), mr)
def test_E():
assert E(z, 0) == z
assert E(0, m) == 0
assert E(i * pi / 2, m) == i * E(m)
assert E(z, oo) == zoo
assert E(z, -oo) == zoo
assert E(0) == pi / 2
assert E(1) == 1
assert E(oo) == I * oo
assert E(-oo) == oo
assert E(zoo) == zoo
assert E(-z, m) == -E(z, m)
assert E(z, m).diff(z) == sqrt(1 - m * sin(z) ** 2)
assert E(z, m).diff(m) == (E(z, m) - F(z, m)) / (2 * m)
assert E(z).diff(z) == (E(z) - K(z)) / (2 * z)
r = randcplx()
assert td(E(r, m), m)
assert td(E(z, r), z)
assert td(E(z), z)
mi = Symbol("m", real=False)
assert E(z, mi).conjugate() == E(z.conjugate(), mi.conjugate())
assert E(mi).conjugate() == E(mi.conjugate())
mr = Symbol("m", real=True, negative=True)
assert E(z, mr).conjugate() == E(z.conjugate(), mr)
assert E(mr).conjugate() == E(mr)
assert E(z).rewrite(hyper) == (pi / 2) * hyper((-S.Half, S.Half), (S.One,), z)
assert tn(E(z), (pi / 2) * hyper((-S.Half, S.Half), (S.One,), z))
assert E(z).rewrite(meijerg) == -meijerg(((S.Half, S(3) / 2), []), ((S.Zero,), (S.Zero,)), -z) / 4
assert tn(E(z), -meijerg(((S.Half, S(3) / 2), []), ((S.Zero,), (S.Zero,)), -z) / 4)
assert E(z, m).series(z) == z + z ** 5 * (-m ** 2 / 40 + m / 30) - m * z ** 3 / 6 + O(z ** 6)
assert E(z).series(
z
) == pi / 2 - pi * z / 8 - 3 * pi * z ** 2 / 128 - 5 * pi * z ** 3 / 512 - 175 * pi * z ** 4 / 32768 - 441 * pi * z ** 5 / 131072 + O(
z ** 6
)
def test_F():
assert F(z, 0) == z
assert F(0, m) == 0
assert F(pi * i / 2, m) == i * K(m)
assert F(z, oo) == 0
assert F(z, -oo) == 0
assert F(-z, m) == -F(z, m)
assert F(z, m).diff(z) == 1 / sqrt(1 - m * sin(z) ** 2)
assert F(z, m).diff(m) == E(z, m) / (2 * m * (1 - m)) - F(z, m) / (2 * m) - sin(2 * z) / (
4 * (1 - m) * sqrt(1 - m * sin(z) ** 2)
)
r = randcplx()
assert td(F(z, r), z)
assert td(F(r, m), m)
mi = Symbol("m", real=False)
assert F(z, mi).conjugate() == F(z.conjugate(), mi.conjugate())
mr = Symbol("m", real=True, negative=True)
assert F(z, mr).conjugate() == F(z.conjugate(), mr)
assert F(z, m).series(z) == z + z ** 5 * (3 * m ** 2 / 40 - m / 30) + m * z ** 3 / 6 + O(z ** 6)
