If you're working in deg, -110, -70, 10, 50, 130, 170 etc. Try drawing the question as a graph to get a better idea of how it works. You can start by simplifying to sin(3x) = 0.5 and then use the fact that sin(30) = 0.5 to get your answers.
If you're working in deg, -110, -70, 10, 50, 130, 170 etc. Try drawing the question as a graph to get a better idea of how it works. You can start by simplifying to sin(3x) = 0.5 and then use the fact that sin(30) = 0.5 to get your answers.