Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

If sin6θ + cos6θ = \(\frac{1}{3}\), 0° < θ < 90°, then find the value of 2sinθ.cosθ

Options:

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

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

\(\frac{\sqrt {6}}{6}\)

\(\frac{\sqrt {7}}{3}\)

Correct Answer:

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

Explanation:

⇒ sin6θ + cos6θ = 1 - 3 sin2θ.cos2θ

⇒ \(\frac{1}{3}\) = 1 - 3 sin2θ.cos2θ

⇒ sin2θ.cos2θ = \(\frac{2}{9}\)

⇒ sinθ.cosθ = \(\frac{\sqrt {2}}{3}\)

Now

⇒ 2 sinθ.cosθ = \(\frac{2\sqrt {2}}{3}\)