If tan2θ = 1-a2
find the value of secθ + tan3θ cosecθ.
Answer & explanation
Correct answer: option 3
We have to find secθ + tan3θ cosecθ
= secθ + tan2θ×\(\frac{sinθ}{cosθ}\)×cosecθ
= secθ + tan2θsecθ
= secθ (1+tan2θ) (secθ=\(\sqrt {1+tan^2θ}\))
= \(\sqrt {1+tan^2θ}\)(1+tan2θ)
⇒ \( {(1+tan^2θ)}^{\frac{1}{2}+1} \)
⇒ \( {(1+tan^2θ)}^{\frac{3}{2}} \)
⇒ \( {(1+1-a^2)}^{\frac{3}{2}} \)
=\( {(2 - a^2)}^{\frac{3}{2}} \)