∫secx(2+secx)(1+2secx)2dx=f(x)+c, where C is constant of integration and f(0) = 0, then ∫π0f(x)dx is equal to
ln 3
∫1cosx(2+1cosx)(1+2cosx)2dx=∫2cosx+1cosx+22∫cosx(coxx+2)+sin2x(1+2secx)2dx=∫cosxcosx+2dx+∫sin2x(cosx+2)2=1cosx+2sinx+∫−sin2x(cosx+2)2sinxdx+∫sin2x(cosx+2)2dx=sinxcosx+2+C