Summary:
The trig addition formulas are used to go even further with evaluating angles for sine, cosine and tangent. These formulas are used to evaluate the angles of sine, cosine and tangent that are not on the chart or unit circle. The special angles are still used to simplify a sum or difference. ex: 75o = (30o + 45o). The three formulas are:
1. sin (A +B) = sin A cos B + cos A sin B or sin (A-B) = sin A cos B - cos A sin B
2. cos (A+B) = cos A cos B - sin A sin B or cos (A-B) = cos A cos B + sin A sin B
3. tan (A+B) = tan A + tan B/1 - tan A tan B or tan (A-B) = tan A - tan B/1 + tan A tan B
Problems are either given in the more complex part of the equation and are asked to be simplified or you are told to evaluate sin, cos or tan of an angle.
Pages 380 to 386 are the pages in the textbook of this section (TAF-1).

Sum and Difference Formula Websites
http://www.themathpage.com/atrig/trigonometric-identities.htm#sum
http://oakroadsystems.com/twt/sumdiff.htm
http://www.algebralab.org/lessons/lesson.aspx?file=Trigonometry_TrigSumDifference.xml

IMovie/Keynote:


Practice Problems:
1. Evaluate sin(15)
2. Evaluate cos(7π/12)
3. Evaluate tan(195)
4. Simplify cos95˚cos65˚+sin95˚sin35˚