cotθ+cosecθ−1cotθ−cosecθ+1=
sinθ1+cosθ
sinθ1−cosθ
1−cosθsinθ
cosθ1−sinθ
1=cosec2θ−cot2θ⇒cosecθ−cotθ=1cosecθ+cotθ ∴cotθ+cosecθ−1cotθ−cosecθ+1=cosecθ+cotθ=1+cosθsinθ=sinθ1-cosθ