# What is the derivative of  tan^ -1(3x^2)?

$\frac{6 x}{1 - 9 {x}^{4}}$
$\frac{d}{\mathrm{dx}} \left({\tan}^{- 1} \left(3 {x}^{2}\right)\right)$
$= \frac{1}{1 - {\left(3 {x}^{2}\right)}^{2}} \cdot \frac{d}{\mathrm{dx}} \left(3 {x}^{2}\right)$
$= \frac{1}{1 - 9 {x}^{4}} \cdot 3 \cdot 2 x$
$= \frac{6 x}{1 - 9 {x}^{4}}$