Product to Sum and Sum to Product Formulas

I derive two of the eight formulas of Product to Sum and Sum to Product and then work through 5 examples at 7:02 10:07 13:00 18:50 and 23:02 http://www.youtube.com/timedtext_vide... Check out http://www.ProfRobBob.com/, there you will find my lessons organized by class/subject and then by topics within each class. Find free review test, useful notes and more at http://www.mathplane.com/ If you'd like to make a donation to support my efforts look for the "Tip the Teacher" button on my channel's homepage    / profrobbob