The correct option is A 16log(1−cos x)+12log(1+cos x)−23log(1+2cos x)+c
∫dxsin x(1+2cos x)
=∫sin x dxsin2x(1+2cos x)=∫sin x dx(1−cos x)(1+cos x)(1+2cos x)
Let cos x = t
∴∫−dt(1−t)(1+t)(1+2t)=∫(−16(1−t)+12(1+t)−43(1+2t))dt
=16log(1−t)+12log(1+t)−23log(1+2t) with t=cos x