Question

Find the value of cos(2010°)
1. \(-\frac{\sqrt3}{2}\)
2. \(-\frac{1}{2}\)
3. \(-\frac{1}{\sqrt2}\)
4. \(\frac{1}{2}\)

Answer 1

Correct Answer - Option 1 : \(-\frac{\sqrt3}{2}\)

Concept:

cos (2nπ ± θ) = cos θ

cos (90 + θ) = -sin θ

 

Calculation:

Here,  cos(2010°)

⇒ cos (6 × 360° - 150°)

= cos(150°)            (∵ cos (2nπ ± θ) = cos θ)

= cos(90° + 60°)

= - sin(60°)            (∵ cos (90 + θ) = -sin θ)

= \(-\frac{\sqrt3}{2}\)

Hence, option (1) is correct.