Your method is fine. Of course you will need to try to get all the solutions in the unit circle and all multiples of added to them...
So I'm wondering. When I have an equation like:
can I divide 0.766 by 2 and take the arcsine of 0.383 to find my x? My friend claims that you cannot divide by 2 for some reason and my text books sort of states the same...Which is algebraically wrong..