Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If cosec2θ + cot2θ = 3\(\frac{1}{2}\), 0° < θ < 90°, than (cosθ + sinθ) is equal to:

Options:

\(\frac{\sqrt {5}+2}{ 2}\)

\(\frac{\sqrt {5}+2}{ 7}\)

\(\frac{\sqrt {5}+2}{ 5}\)

\(\frac{\sqrt {5}+2}{ 3}\)

Correct Answer:

\(\frac{\sqrt {5}+2}{ 3}\)

Explanation:

cosec2θ + cot2θ = 3\(\frac{1}{2}\)

1+cot2θ + cot2θ = 3\(\frac{1}{2}\)

2cot2θ = \(\frac{7}{2}\) - 1

cot2θ =\(\frac{5}{4}\)

cotθ =\(\frac{\sqrt {5}}{2}\)=\(\frac{B}{P}\)

H=\(\sqrt {(\sqrt {5})^2+(2)^2}\) = 3

⇒ cosθ + sinθ =\(\frac{P+B}{H}\) = \(\frac{\sqrt {5}+2}{ 3}\)