# How to find derivatives with simplified form for this equation? (x^2-1)/(x^2+1)

Mar 17, 2015

$y ' = \frac{2 x \left({x}^{2} + 1\right) - 2 x \left({x}^{2} - 1\right)}{{x}^{2} + 1} ^ 2 = \frac{2 x \left({x}^{2} + 1 - {x}^{2} + 1\right)}{{x}^{2} + 1} ^ 2 =$

$= \frac{4 x}{{x}^{2} + 1} ^ 2$.