Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If tan2θ = 1-a2

find the value of secθ + tan3θ cosecθ.

Options:

\( {(2 - a)}^{\frac{1}{2}} \)

\( {(a - 2)}^{\frac{3}{2}} \)

\( {(2 - a^2)}^{\frac{3}{2}} \)

\( {a}^{\frac{3}{2}} \)

Correct Answer:

\( {(2 - a^2)}^{\frac{3}{2}} \)

Explanation:

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)

⇒ \( {(1+tan^2θ)}^{\frac{1}{2}+1} \)

⇒ \( {(1+tan^2θ)}^{\frac{3}{2}} \)

⇒ \( {(1+1-a^2)}^{\frac{3}{2}} \)

=\( {(2 - a^2)}^{\frac{3}{2}} \)