Question

Find the exact value of cos(x/2) if sin x = 3/4 and x is in quadrant II.

==> I got ã(4-ã7)/2. Is this correct?

Answer 1

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]

Answer 2

Oops, yeah those were supposed to be radicals :) thanks so much!!!!