Let I=∫sin2x+3cosx−3sin2xdx=−∫1−cos2x+3cosx−3sin2xdx=∫−cos2x+3cosx−22sinx⋅cosxdx=∫−t2+3t−22t(−dt)Put cosx=tsinxdx=−dt=∫t2−3t+22tdt=∫(t−2)(t−1)2tdt=2∫(t−22−t−11)dt=2[2ln(t−2)−ln(t−1)]=2ln(t−1(t−2)2)=ln(t−1)2(t−2)4+C=ln((cosx−1)2(cosx−2)4)+C