Section 4.1

#9-22. In each case, our job is to simplify the expression. Remember the strategies discussed in class (and shown on the website, Demo Section 4.1): get a common argument, get a common trig function, etc. For example, on #9, convert all of the trig functions to sines and/or cosines, then see what cancels.

#23-84. In each case, we need to verify the identity. That is, we need to manipulate one side of the equation to make it look like the other side. (Or we could manipulate both sides to meet somewhere in the middle.) Remember the strategies discussed in class (and shown on the website, Demo Section 4.1): get a common argument, get a common trig function, etc. For example, on #25, work on the left-hand side to try to make it look like the right-hand side. On the left, try converting each trig function into sines and/or cosines, then see what cancels. For another example, on #29, try the sine and/or cosine thing on the left, then try to get a common denominator.