\(f(x)= {1\over 1-x^2}\) Thanks to my CAS I have the result but I don't know how it got it.
\(f(x)= {1\over 1-x^2}\\ f(x)= (1-x^2)^{-1}\\ f'(x)= -1(1-x^2)^{-2}*-2x\\ f'(x)= \frac{2x}{(1-x^2)^{2}}\\\)
