Question

sin3x=sinx

Answer 1

You want the solutions of x?

Answer 2

\[\sin3x-sinx=0\]
Use the following now:
\[sinA-sinB=2\sin[(A-B)/2]\cos[(A+B)/2]\]
Can you do it from here?

Answer 3

wow, makes things a lot easier with that formula. I did it with
\[\sin(A+B)=sinAcosB + sinBcosA\]

Answer 4

\[\sin(2x+x)-sinx=0\]