my question is Why are there 3 solutions in this trigonometric equation $sin\theta = 0$? I thought since the range for the angle is between 0 and 360 it has 2 solutions? I tried and I have got 2 solutions which are 0, and 180 but apparently there is 1 more solution. Can someone please explain this and if you can, also tell me what do I do if I obtain a negative angle? For example in this equation $tan(\theta-50)=-1.7$, I solved and got a negative angle, how do I proceed to the next step? Please help Thank you!