Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If sec2θ + tan2θ = 3\(\frac{1}{2}\), 0° < θ < 90°, than (cosθ + sinθ) is equal to:

Options:

\(\frac{1+\sqrt {5}}{3}\)

\(\frac{2+\sqrt {5}}{3}\)

\(\frac{1+\sqrt {5}}{6}\)

\(\frac{9+2\sqrt {5}}{6}\)

Correct Answer:

\(\frac{2+\sqrt {5}}{3}\)

Explanation:

sec2θ + tan2θ = 3\(\frac{1}{2}\)

1+tan2θ + tan2θ = 3\(\frac{1}{2}\)

2tan2θ = \(\frac{7}{2}\) - 1

tan2θ =\(\frac{5}{4}\)

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

H=\(\sqrt {(\sqrt {5})^2+(2)^2}\)=3

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