2 tan−1(cos x)=tan−1(cosec2x),then x=
2 tan−1(cosx)=tan−1(cosec2x)⇒tan−1(2cosx1−cos2x)=tan−1(1sin2x)⇒2 cos xsin2x=1sin 2x⇒2 cos x=1⇒x=π3.