1. I don't understand coumpound angle formulae, for example sin(x+y), sin(x-y) etc. I'm supposed to solve using angles in the special triangles--so I use angles like 45, 30, 60, or those angles converted into radians--and add them to get the answer. For example: sin15 would be solved using sin(x-y) or sin (45-30). But when I have a question like "find the exact value of tan165", I'm lost as to what to do. Question: Solve the following using exact values: a)tan165 b)tan 13π/12 2. Relevant Eqns: tan(x+y)= tanx+tany / 1-tanxtany tan(x-y)= tanx-tany / 1+tanxtany 3. I'm not at all sure how to go about solving it.