Half Angle Formulas T, 11.0: Students demonstrate an understanding of half-angle and double- angle formulas for sines and cosines and can use those formulas to prove and/or simplify other trigonometric identities.

Half Angle Formulas Objectives Know the half angle identities Verify more complex trigonometric identities using the basic trigonometric identities, Pythagorean identities, co-function identities, odd/even identities, sum & difference identities, double angle identities, half- angle identities and justify each step in the verification process. Key Words Degrees Radians Half-Angle Identities

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Half Angle Identities Take out your Unit Circle…

Using the Half Angle Identity

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Conclusions Summary Name the quadrant in which the terminal side lies – X is a second quadrant angle. In which quadrant does 2x lie? – x/2 is a first quadrant angle. In which quadrant does x lie? Assignment Half Angle Formulas – Page 453 – #(6,7,14-18,33)