Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If cosθ - sec θ = 3 , find the value of cos2θ + sec2θ .

Options:

13

9

11

15

Correct Answer:

11

Explanation:

Formula I → [ cosθ = \(\frac{1}{secθ}\)]

Formula II → [If x - \(\frac{1}{x}\) = n and x2 + \(\frac{1}{x^2}\) = n2 + 2]

cosθ - \(\frac{1}{cosθ}\) = 3

⇒ cos2θ + \(\frac{1}{cos^2θ}\) = (3)2 + 2

⇒ cos2θ + sec2θ = 9 + 2 = 11