Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If tan θ + sec θ = x; what is the value of tanθ.secθ ?

Options:

\(\frac{1}{4}\)(x2 + 2x)

\(\frac{1}{4}\)(x2 - 2x)

\(\frac{1}{4}\)(x2 + \(\frac{1}{x^2}\))

\(\frac{1}{4}\)(x2 - \(\frac{1}{x^2}\))

Correct Answer:

\(\frac{1}{4}\)(x2 - \(\frac{1}{x^2}\))

Explanation:

tan θ + sec θ = x

⇒ tan θ - sec θ = \(\frac{1}{x}\)

4tanθ.secθ = (tanθ + secθ)2 - (tanθ - secθ)2

⇒ 4tanθ.secθ = x2 - \(\frac{1}{x^2}\)

⇒ tanθ.secθ = \(\frac{1}{4}\)(x2 -  \(\frac{1}{x^2}\))