Question

Prove that cot θ. tan (90° - θ) - sec (90° - θ). cosec θ + 1 = 0.

Answer 1

LHS = cot θ. tan (90° - θ) - sec (90° - θ). cosec θ + 1

= cot θ. cot θ - cosec θ. cosec θ + 1

= (cot²θ - cosec²θ) + 1

= - 1 + 1 = 0
= RHS
Hence proved.