Неопределенный интеграл

.. = (1/2)*S (sin(2x)/cos^3(2x) ) d(2x) = (1/2)*S (-1/cos^3(2x) ) d(cos(2x)) =  = (-1/2)*S cos^(-3)(2x) d(cos(2x)) = (-1/2)*(1/(-3+1) )*cos^(-3+1)(2x) + C =   = (-1/2)*(-1/2)*(1/cos^2(2x))+C = (1/4)*(1/cos^2(2x) ) +C,