Question 607195
Hint: use the idea that <img src="http://latex.codecogs.com/gif.latex?\Large \sin^2(x) + \cos^2(x) = 1" title="x" />. We can solve for cosine to get <img src="http://latex.codecogs.com/gif.latex?\Large \cos(x) = \pm\sqrt{1-\sin^2(x)}" title="x" />


Note: the sign of the result will depend on which quadrant the angle lies.