Objective

To use the sum and difference formulas to evaluate each trigonometry angle without using a calculator. 

Web Resources

http://www.mathwords.com/s/sum_difference_identities.htm        List of the sum and difference formulas

http://www.regentsprep.org/Regents/math/algtrig/ATT14/formulalesson.htm        Notes and Examples

http://hotmath.com/hotmath_help/topics/sum-and-difference-identities.html        Formulas and worked out examples

http://worksheets.tutorvista.com/sum-and-difference-identities-worksheet.html        Practice problems with solutions

Lesson Video

Pay Attention to the Following: