SOLUTION: im stuck on this problem Given that sin theta = .6820 and that theta is in quadrant I. find cos theta/2?

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Question 817411: im stuck on this problem
Given that sin theta = .6820 and that theta is in quadrant I. find cos theta/2?
Found 2 solutions by ewatrrr, lwsshak3:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

sin θ = .6820,   θ = 43°

cos (43°/2)  = .9304

Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Given that sin theta = .6820 and that theta is in quadrant I. find cos theta/2?
***
cos%28x%2F2%29=sqrt%28%281%2Bcos%28x%29%29%2F2%29
cos(x)=√(1-sin^2x)=√(1-(.682)^2)≈√(1-.4651)≈√.5349≈.7314

..
calculator check:
sin(x)=.6820
x≈43˚
x/2≈21.5˚
cos(x/2)≈cos(21.5˚)≈0.9304
value as calculated≈0.9304