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 don't understand how RS=LS and thanks