Derivative of trigonometric functions python

Question

I am working on a little side project and building a calculator for different numerical analysis methods. What I am struggling with is calculating derivatives of trigonometric functions. For calculations of derivatives I am using sympy and math Python library.

print(sym.diff(math.cos(x)))

The correct answer for this should be -sin(x) , however I get:

TypeError: can't convert expression to float

Is there any way I can correctly calculate derivatives of trigonometric functions?

Answer 1

SymPy has its own functions which know how to be differentiated. math versions only know how to give a numerical answer for numerical input.

>>> from sympy import sin
>>> from sympy.abc import x
>>> sin(x).diff(x)
cos(x)

Answer 2

This should give you an idea of how to go about it.

import sympy as sym
import math

x=sym.symbols('x') 
def f(x):
    return x**2

print(sym.diff(f(x)))