Posted by **hayden** on Sunday, February 22, 2009 at 8:18pm.

cos^2 (a+x) -sin^2 a=cos x * cos(2a+x)

- precalc and trig -
**Reiny**, Sunday, February 22, 2009 at 8:22pm
see

http://www.jiskha.com/display.cgi?id=1235346549

don't tell my I did all that work, and you didn't even look at it.

- precalc and trig -
**hayden**, Sunday, February 22, 2009 at 8:43pm
i posted a sorry. i posted this twice on that one. And i dont understand how RS=LS and thanks

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