If cosec θ=2, show that cotθ+sinθ1+cosθ = 2.
We know that cotθ=cosθsinθ
cotθ+sinθ1+cosθ
=cosθsinθ+sinθ1+cosθ
= cosθ(1+cosθ)+sin2θsinθ(1+cosθ)
= cosθ+cos2θ+sin2θsinθ(1+cosθ)
∵cos2θ+sin2θ=1
= cosθ+1sinθ(1+cosθ)
=1sinθ
= cosecθ=2
Hence proved.