hscishard
Active Member
Re: another question
Nice. That's much quickersin 2x + sin 4x = sin 3x
sin (3x - x) + sin (3x + x) = sin 3x
sin 3x cos x - sin x cos 3x + sin 3x cos x + sin x cos 3x = sin 3x
2sin 3x cos x = sin 3x
sin 3x (2cos x - 1) = 0
cos x = 1/2
=> x = 2nπ ± π/3 for integer n
sin 3x = 0
=> 3x = kπ
=> x = kπ/3 for integer k