The derivative of (1 +cos2x) [whole square] using chain rule. Share with your friends Share 1 Rishabh Mittal answered this Let y=1+cos2x2Differentiating wrt x both sides , we gety'=21+cos2x d1+cos2xdx=21+cos2x 0+2 cos x dcos xdx=21+cos2x 2 cos x -sin x=-4 sin x cos x 1+cos2x=-2 sin 2x 1+cos2x ANS... 0 View Full Answer