Question

Найти производную y=arctg^2 x

Answer 1

$y=\mathrm{arctg}^2 x$

$y'=2\mathrm{arctg}\,x\cdot (\mathrm{arctg}\,x)'=2\mathrm{arctg}\,x\cdot \dfrac{1}{1+x^2} = \dfrac{2\mathrm{arctg}\,x}{1+x^2}$