Simplifying Trig Identities
Sum/Difference
Double angle
Half angle
Other websites
Works Cited
Click here for basics on trig identities-
http://www.intmath.com/analytic-trigonometry/1-trigonometric-identities.php
Click here for more info and a video on simplifying identities-
http://www.onlinemathlearning.com/trigonometric-identities.html