Question

Найдите интегралы tg3x/cos^2 3x*dx

Answer 1

int (1 + tg^3 x)/cos^2 x dx = int (1 + tg^3 x) d(tg x) = | tg x = t | =
= int (1 + t^3) dt = t + 1/4 * t^4 + C = | t = tg x | = tg x + 1/4 * tg^4 x + C