def test_ADmath_cosr():
f = ADmath.cos(4)
assert f == np.cos(4)
def test_sinxcosx():
x = ADnum(0, der=1)
f = ADmath.sin(x) * ADmath.cos(x)
assert f.val == np.sin(0) * np.cos(0)
assert f.der == -(np.sin(0)**2) + np.cos(0)**2
def test_ADmath_cos():
f = ADmath.cos(ADnum(4, der=1))
assert f.val == np.cos(4)
assert f.der == -np.sin(4)
assert len(f.graph) == 1