This self checking worksheet is a little harder than the worksheet entitled "Identities - Basic 1" and "Identities - Basic 2." Not only are Pythagorean Identities and Reciprocal functions used, but also even/odd functions. Also the student is required to factor most functions. My students have a lot of trouble with these problems. The factoring of trig functions makes them crazy!! Upon completion of this worksheet, the solution to a riddle is unveiled.