Question

vi) sin 3x - 2 cos^x = 0​

Answer 1

Answer:

sin3x - sinx = 1/2

2cos(2x)sin(x) = 1/2

cos(2x)sin(x) = 1/4

(1 - 2sin²(x))(sin(x)) = 1/4

sin(x) - 2sin³(x) - 1/4 = 0

2sin³(x) - sin(x) + 1/4 = 0

2u³ - u + ¼ = 0