(i) cosecθ+cotθcosecθ−cotθ=(cosecθ+cotθ)2=1+2cot2θ+2cosecθcotθ
(ii) secθ+tanθsecθ−tanθ=(secθ+tanθ)2=1+2tan2θ+2secθtanθ
(i) cosecθ+cotθcosecθ−cotθ=(cosecθ+cotθ)2=1+2cot2θ+2cosecθcotθcosecθ+cotθcosecθ−cotθ=cosecθ+cotθcosecθ−cotθ×cosecθ+cotθcosecθ+cotθ=(cosecθ+cotθ)2cosec2θ−cot2θ=(cosecθ+cotθ)21=(cosecθ+cotθ)2 [First term]=cosec2θ+cot2θ+2cosecθcotθ=(1+cot2θ)+cot2θ+2cotθcosecθ=1+2cot2θ+2cotθcosecθ [Second term]
(ii) secθ+tanθsecθ−tanθ=(secθ+tanθ)2=1+2tan2θ+2secθtanθsecθ+tanθsecθ−tanθ=secθ+tanθsecθ−tanθ×secθ+tanθsecθ+tanθ=(secθ+tanθ)2sec2θ−tan2θ=(secθ+tanθ)2 [First term]=sec2θ+tan2θ+2secθtanθ=1+tan2θ+tan2θ+2secAtanA=1+2tan2A+2secθtanθ [Second term]