We increase our ambitions and introduce a slightly more complicated function
$$ f(x) =\sqrt{x^2+exp{x^2}}, $$with derivative
$$ f'(x) =\frac{x(1+\exp{x^2})}{\sqrt{x^2+exp{x^2}}}. $$The corresponding SymPy code reads
from __future__ import division
from sympy import *
x = symbols('x')
expr = sqrt(x*x+exp(x*x))
simplify(expr)
derivative = diff(expr,x)
print(python(expr))
print(python(derivative))