Question

y=1+ tg^2x
нужна производная

Answer 1

$y=tg^2x;\ y'=(tg^2x)'=2tgx(tgx)'=2tgx(frac{sin x}{cos x})'=\ =2tgx(frac{(sin x)'cos xsin x(cos x)'}{cos^2x})=2tgxfrac{cos^2x+sin^2x}{cos^2x}=\ =2 frac{tgx}{cos^2x}=2frac{sin x}{cos^3x}$