(i) (sec2θ−1)cot2θ=1 (ii) (sec2θ−1)(cosec2θ−1)=1
(iii) (1−cos2θ)sec2θ=tan2θ
(i) (sec2θ−1)cot2θ=1L.H.S=(sec2θ−1)cot2θ=tan2θ×cot2θ=(1cot2θ)×(cotθ)=1=R.H.S
(ii) (sec2θ−1)(cosec2θ−1)=1L.H.S=(sec2θ−1)(cosec2θ−1)=(tan2θ)(1sin2θ−1)=(tan2θ)(1−sin2θsin2θ)=(sin2θcos2θ)(cos2θsin2θ)=1=R.H.S
(iii) (1−cos2θ)sec2θ=tan2θL.H.S=(1−cos2θ)sec2θ=(sin2θ)(1cos2θ)=sin2θcos2θ=tan2θ=R.H.S