JEE Main20199 Jan 2019Evening ShiftMathematicsTrigonometric EquationsActual
If 0 ≤ x < π 2 , then the number of values of x for which sin x - sin 2 x + sin 3 x = 0 , is:
Options
- A4
- B3
- C2
- D1
Correct answer
C. 2
Step-by-step solution
sin x - sin 2 x + sin 3 x = 0 ⇒ sin x + sin 3 x - sin 2 x = 0 ⇒ 2 sin 2   x   . cos x - sin 2 x = 0 ⇒ sin 2 x = 0 or cos x = 1 2 ⇒ 2 x = 0 or x = π 3 ⇒ x = 0 or   x = π 3 ∴ Number of solutions = 2