Question

sin(x)+2sin(10x)cos(3x)=0

Answer 1

sin x+2* 1/2*(sin 13x+sin 7x)=0
sin x+sin 13x+sin 7x=0
2sin7x*cos6x+sin7x=0
sin7x*(2cos6x+1)=0
sin7x=0
7x=Pi*k
x=Pi*k/7
cos6x=- 1/2
6x=+-2Pi/3+2Pi*k
x=+-Pi/9+Pi*k/3