Найти неопределенный интеграл ∫ x^2dx/cos^2(3-x^3)
[m]\int \frac{x^2\ dx}{cos^2(3-x^3)}[/m] Замена y = 3 - x^3; dy = -3x^2 dx; x^2 dx = -1/3*dy [m]-\frac{1}{3}\int \frac{dy}{cos^2(y)} = -\frac{1}{3} \cdot tg(y) + C= -\frac{1}{3} \cdot tg(3-x^3) + C[/m]