Dear all,

I'm solving 2 sums

a) 1 - cos x = (sqrt 3) sin x

By squaring both sides, and using the sin^2x + cos^2x = 1 relation,

I get 2 cos^2x - cos x - 1=0

Solving, I get x = 120, 240 (for 2nd, 3rd quadrant) and 0, 360 (for 1st, 4th quadrant)

May I know why 240 is rejected?

b) 2 + sin x = 4 cos x

Similarly, I'm solving down to 17 sin^2x + 4 sinx - 12 = 0

I get sin x = 0.7307 or -0.966

Hence, x - 46.9 or 133.1 ; 285 or 255

Why is 133.1 and 255 rejected?

Thanks