Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If b cosθ = a, then find the value of cosec2θ + cot2θ.

Options:

1

\(\frac{b^2\;+\;a^2}{a^2\;-\;b^2}\)

\(\frac{b\;+\;a}{a^2\;-\;b^2}\)

\(\frac{b^2\;+\;a^2}{b^2\;-\;a^2}\)

Correct Answer:

\(\frac{b^2\;+\;a^2}{b^2\;-\;a^2}\)

Explanation:

cosθ =\(\frac{a}{b}\)=\(\frac{Base}{Hyp.}\)

Perp. =\(\sqrt {b^2-a^2}\)

⇒ cosec2θ + cot2θ = \(\frac{hyp^2}{Perp^2}\) + \(\frac{base^2}{Per^2}\) = \(\frac{b^2}{(\sqrt {b^2-a^2})^2}\) + \(\frac{a^2}{(\sqrt {b^2-a^2})^2}\)

= \(\frac{b^2}{b^2-a^2}\) + \(\frac{a^2}{b^2-a^2}\)

= \(\frac{b^2\;+\;a^2}{b^2-a^2}\)