Question

3) Value of 9 cot²o-qcosec²o is​

Answer 1

Answer:

To find: 9 cot2 θ – 9 cosec2 θ

Consider 9 cot2 θ – 9 cosec2 θ = 9 (cot2 θ – cosec2 θ)

Now ∵ 1 + cot2 θ = cosec2 θ

⇒ cot2 θ – cosec2 θ = – 1

⇒ 9 cot2 θ – 9 cosec2 θ = 9 (cot2 θ – cosec2 θ) = 9 ( – 1) = – 9