Tolong bantu ya kaka !! 1. Sin 2x + sin 3x 2. Cos 3x + cos 7x 3. Sin 3x - sin 8x

Trigonometri

1.sin 2x + sin 3x
= 2 sin (2x+3x)/2 cos(2x-3x)/2
= 2 sin 5x/2 cos -x/2

2. cos3x+ cos 7x
= 2 cos (3x+7x)/2 cos (3x-7x)/2
= 2 cos 5x cos -2x
= 2 cos 5x cos 2x

3.sin3x - sin 8x
= 2 cos(11x/2) sin (-5x)/2
= -2 cos 11x/2 sin 5x/2