Posted by Evelina on Saturday, November 12, 2011 at 9:06am.
Are you sure the first one isn't
( 1 + 2sina cosa)/(cosa + sina)^2 ?
because then it would be
= (sin^2a + cos^2a + 2sina cosa)/(cosa + sina)^2
= (sina + cosa)^2/(cosa + sina)^2
= 1
2nd:
(sina + cosa)/(1 - 2sin^2a)= (sina + cosa)/(sin^2a + cos^2a - 2sin^2a)
= sina+cosa)/( cos^2a - sin^2a)
= (sina + cosa)/( cosa - sina)(cosa+sina) )
= 1/(cosa - sina)
oh yes, I wrote the first one wrong.
THANK YOU
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