Today Joshua and I discussed the sum and difference formulas for trig. We looked it up and unfortunately Joshua will have to memorize them as there will be no formula sheet in the AP exam. They seem difficult at first, but with practice and repetition, I feel confident Josh will have them memorized. We also worked on the Double angle formulas which we derived using the sum and difference formulas. Next we used all of these formulas to solve trig equations under a given domain.