Posted by Emily on Monday, May 3, 2010 at 8:52pm.
Find the exact value of cos(x/2) if sin x = 3/4 and x is in quadrant II.
==> I got ã(4ã7)/2. Is this correct?

Math Analysis  Reiny, Monday, May 3, 2010 at 9:24pm
I can't read your symbols, but
if sinx = 3/4 in II then
cos x = √7/4
cosx = 2cos^2 (x/2)  1
√7/4 + 1 = 2cos^2 (x/2)
(4√7)/8 = cos^2 (x/2)
cos x/2 = √[(4√7)/8]

Math Analysis  Emily, Monday, May 3, 2010 at 9:27pm
Oops, yeah those were supposed to be radicals :) thanks so much!!!!
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