# What is the derivative of y=1/(4-x^2) ?

$\frac{\mathrm{dy}}{\mathrm{dx}} = \frac{2 x}{4 - {x}^{2}} ^ 2$
$y = \frac{1}{4 - {x}^{2}} = {\left(4 - {x}^{2}\right)}^{-} 1.$
$\frac{\mathrm{dy}}{\mathrm{dx}} = - 1 {\left(4 - {x}^{2}\right)}^{-} 2 \left(- 2 x\right) = \frac{2 x}{4 - {x}^{2}} ^ 2$