I don't think you won't be able to solve this algebraicly, try a numerical approximation using a computer or (graphical) calculator.
It can be simplified down toOriginally Posted by TD!
but since the next stage is to look up an inverse trig function the effort
of simplifying is probably not worth it and one might as well go straight
for a numerical solution.
The first solution is
The only advantage of simplifiing is that it will give you all of the solutions.
Use the sum formula to get,Originally Posted by totalnewbie
Recognzing this sum formula for sine we have,
(As CaptainBlack said)
Which can be written more elegantly as,