Charlie

we just took test again this week. two of the things on those so called test were the formulas sin(alpha +\- beta) = sinalpha cosbeta +\- cosalpha sinbeta and cos (alpha +/- beta) = cosalpha cosbeta -/+ sinalpha sinbeta. For these you just basically plug in the numbers or letters. You make get the front or the back of the formula. Or maybe even just one angle. For example: If they give you to solve for sin (x -z). You plug the x and z into the other half of the formula so that you get sinx cosz - cosx sinz. This doesn't simplify any smaller. Another example: if they give you the problem cosl cosp + sinl sinp. you have to simplify into either sin(alpha +/- beta) or sin (alpha +/- beta). In this formula you recognize that it is the cos formula. So to simplify you take the alpha and the beta and notice the middle sign is +. So the answer is cos (l - p)