passwella.
Menu

WAEC Further Mathematics 2021 Question 29

Question 29

Trigonometry

If √5 cos x + √15 sin x = 0, for 0° < x < 360°, find the values of x.

  1. A.30° and 150°
  2. B.150° and 210°
  3. C.150° and 330°
  4. D.210° and 330°
Show the answer and explanation

Answer: C (150° and 330°)

Explanation

tan x = −√5/√15 = −1/√3. tan is negative in the 2nd and 4th quadrants: x = 150° or 330°.