Question

sin2x-sinx=0

Answer 1

see that sin(2x) = 2sin(x)cos(x)

so,
sin2x-sinx=0
2sin(x)cos(x) - sin(x)=0
factor out it by take the commons,
sin(x) (2cosx - 1) = 0

each factor must be zero,
sin(x) = 0
solve for x

and
2cos(x) - 1 = 0
solve for x