from sympy import *
from IPython.display import *
init_printing(use_latex=True)
x = Symbol('x')
f = lambda x: sqrt(1-x**2)
fl = ['$f(x) =',latex(f(x)),'$']
display(Latex(''.join(fl)))
2 * integrate(f(x),(x,-1,1))

$f(x) =\sqrt{- x^{2} + 1}$

$$\pi$$