def test_chebyshev():
assert chebyshevt(0, x) == 1
assert chebyshevt(1, x) == x
assert chebyshevt(2, x) == 2*x**2 - 1
assert chebyshevt(3, x) == 4*x**3 - 3*x
assert chebyshevt(-2, x) == 2*x**2 - 1
for n in range(1, 4):
for k in range(n):
z = chebyshevt_root(n, k)
assert chebyshevt(n, z) == 0
pytest.raises(ValueError, lambda: chebyshevt_root(n, n))
for n in range(1, 4):
for k in range(n):
z = chebyshevu_root(n, k)
assert chebyshevu(n, z) == 0
pytest.raises(ValueError, lambda: chebyshevu_root(n, n))
n = Symbol('n')
X = chebyshevt(n, x)
assert isinstance(X, chebyshevt)
assert chebyshevt(n, -x) == (-1)**n*chebyshevt(n, x)
assert chebyshevt(-n, x) == chebyshevt(n, x)
assert chebyshevt(n, oo) == oo
assert chebyshevt(n, 0) == cos(pi*n/2)
assert chebyshevt(n, 1) == 1
assert conjugate(chebyshevt(n, x)) == chebyshevt(n, conjugate(x))
assert diff(chebyshevt(n, x), x) == n*chebyshevu(n - 1, x)
pytest.raises(ArgumentIndexError, lambda: chebyshevt(n, x).fdiff(1))
X = chebyshevu(n, x)
assert isinstance(X, chebyshevu)
assert chebyshevu(n, -x) == (-1)**n*chebyshevu(n, x)
assert chebyshevu(-n, x) == -chebyshevu(n - 2, x)
assert chebyshevu(n, oo) == oo
assert chebyshevu(n, 0) == cos(pi*n/2)
assert chebyshevu(n, 1) == n + 1
assert chebyshevu(-1, x) == 0
assert chebyshevu(-2, x) == -1
assert conjugate(chebyshevu(n, x)) == chebyshevu(n, conjugate(x))
assert diff(chebyshevu(n, x), x) == \
(-x*chebyshevu(n, x) + (n + 1)*chebyshevt(n + 1, x))/(x**2 - 1)
pytest.raises(ArgumentIndexError, lambda: chebyshevu(n, x).fdiff(1))
def test_chebyshev():
assert chebyshevt(0, x) == 1
assert chebyshevt(1, x) == x
assert chebyshevt(2, x) == 2*x**2 - 1
assert chebyshevt(3, x) == 4*x**3 - 3*x
assert chebyshevt(-2, x) == 2*x**2 - 1
for n in range(1, 4):
for k in range(n):
z = chebyshevt_root(n, k)
assert chebyshevt(n, z) == 0
pytest.raises(ValueError, lambda: chebyshevt_root(n, n))
for n in range(1, 4):
for k in range(n):
z = chebyshevu_root(n, k)
assert chebyshevu(n, z) == 0
pytest.raises(ValueError, lambda: chebyshevu_root(n, n))
n = Symbol("n")
X = chebyshevt(n, x)
assert isinstance(X, chebyshevt)
assert chebyshevt(n, -x) == (-1)**n*chebyshevt(n, x)
assert chebyshevt(-n, x) == chebyshevt(n, x)
assert chebyshevt(n, oo) == oo
assert chebyshevt(n, 0) == cos(pi*n/2)
assert chebyshevt(n, 1) == 1
assert conjugate(chebyshevt(n, x)) == chebyshevt(n, conjugate(x))
assert diff(chebyshevt(n, x), x) == n*chebyshevu(n - 1, x)
pytest.raises(ArgumentIndexError, lambda: chebyshevt(n, x).fdiff(1))
X = chebyshevu(n, x)
assert isinstance(X, chebyshevu)
assert chebyshevu(n, -x) == (-1)**n*chebyshevu(n, x)
assert chebyshevu(-n, x) == -chebyshevu(n - 2, x)
assert chebyshevu(n, oo) == oo
assert chebyshevu(n, 0) == cos(pi*n/2)
assert chebyshevu(n, 1) == n + 1
assert chebyshevu(-1, x) == 0
assert chebyshevu(-2, x) == -1
assert conjugate(chebyshevu(n, x)) == chebyshevu(n, conjugate(x))
assert diff(chebyshevu(n, x), x) == \
(-x*chebyshevu(n, x) + (n + 1)*chebyshevt(n + 1, x))/(x**2 - 1)
pytest.raises(ArgumentIndexError, lambda: chebyshevu(n, x).fdiff(1))