What is the answer to this math problem? Please Include the explanation as well.

we need to plug the function f(x) sin²x + sin(x) on the radical graph and see for which x it is when y is under 0, on the intervall 0<x<2pi
We see on the graf that sin²x+sinx < 0 on the interval: 0<x<2pi.
when:
pi<x<1.5pi
and:
1.5pi<x<2pi