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February 28, 2015

February 28, 2015

Posted by **Ashlynn** on Monday, October 19, 2009 at 11:21pm.

- calc -
**Reiny**, Monday, October 19, 2009 at 11:33pmdivide both sides by 2

and you end up with the definition of

cos 2x = cos^2 x - sin^2 x

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