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January 31, 2015

January 31, 2015

Posted by **ama** on Friday, July 6, 2012 at 2:14am.

a. 2sin 22.5 cos 22.5

b. cos^2 105- sin^2 105

- precalculus -
**Damon**, Friday, July 6, 2012 at 4:27ama, use

sin 45 = cos 45 = 1/sqrt 2

b, use

105 = (1/2) 210 which is 180 + 30

so use

sin 210 = -1/2

cos 210 = -sqrt 3/2

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