Sum,+Diff,+Double

=Sum, Difference & Double Angles= =by: Ava, Nick, Chelsea and Allison=

needs a better summary of how to do the 2 types
Sum of Angle Measures Difference of Angle Measures Double-Angle Measures

In mathematics, trigonometric identities are equalities that involve trigonometric functions that are true for every single value of the occurring variables. These identities are useful whenever expressions involving trigonometric functions need to be simplified. An important application is the integration of non-trigonometric functions: a common trick involves first using the substitution rule with a trigonometric function and then simplifying the resulting integral with a trigonometric identity.

This is a correct version



However, some people make the mistake in the fourth step of the problem. You cannot subtract two unlike terms does not equal

Incorrect Version:

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Examples to try:

1) find the exact value of cos105 using sum or difference identities -Answer:

2. Find sin2A if sinA=12/13, cosA=-5/13 -Answer: -120/169