Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If sec2θ + tan2θ = 4\(\frac{1}{2}\), 0° < θ < 90°, than (cosθ + sinθ) is equal to:

Options:

 \(\frac{\sqrt {3}+2}{ √11}\)

 \(\frac{\sqrt {7}+2}{ √7}\)

 \(\frac{\sqrt {7}+2}{ √11}\)

 \(\frac{\sqrt {7}+2}{ 9}\)

Correct Answer:

 \(\frac{\sqrt {7}+2}{ √11}\)

Explanation:

sec2θ + tan2θ = 4\(\frac{1}{2}\)

1+tan2θ + tan2θ = 4\(\frac{1}{2}\)

2tan2θ = \(\frac{9}{2}\) - 1

tan2θ =\(\frac{7}{4}\)

tanθ =\(\frac{\sqrt {7}}{2}\)=\(\frac{P}{B}\)

H=\(\sqrt {(\sqrt {7})^2+(2)^2}\) = √11

⇒ cosθ + sinθ =\(\frac{P+B}{H}\) = \(\frac{\sqrt {7}+2}{ √11}\)