I need to derive this function:

$\displaystyle \frac{2a}{1-x^2-a^2}$

$\displaystyle a$ is a constant

This is how i tried to solve it:

$\displaystyle 2a(1-x^2-a^2)^{-1}$

$\displaystyle \frac{4ax}{(1-x^2-a^2)^2}$

Is that the right answer?

Thanks