Common things to watch out for when solving trignometric equations:
ul
liIs it a "disguised" quadratic equation?/li
liAre your answers valid for the range given in the question?/li
liAre your answers in the correct form (radians vs degrees)?/li
liHave you missed any angles? Remember that every time you do (\arcsin{x}), (\arccos{x}) or (\arctan{x}), there is another angle./li
liFor (y = \arcsin{x}), the other angle is ((180\degree-y))./li
liFor (y = \arccos{x}), the other angle is ((360\degree-y))./li
liFor (y=\arctan{x}), the other angle is ((180\degree+y))./li
liCheck your answers on a graphic calculator![/li]/ul

[b]uSolving trigonometric equations[/u]/b

For (y = \arcsin{x}), the other angle is ((180\degree-y)).
For (y = \arccos{x}), the other angle is ((360\degree-y)).
For (y= \arctan{x}), the other angle is ((180\degree+y)).