SOLUTION: given that sin theta = 1/5 and that the terminal side is in quadrant 1, find exact answers for cos(theta+pi/4)

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Question 851303: given that sin theta = 1/5 and that the terminal side is in quadrant 1, find exact answers for cos(theta+pi/4)
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
given that sin theta = 1/5 and that the terminal side is in quadrant 1, find exact answers for cos(theta+pi/4)
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sin(t) = 1/5
cos%28t%29+=+sqrt%281+-+sin%5E2%28t%29%29+=+2sqrt%286%29%2F5%29
cos(t + pi/4) = cos(t)*cos(pi/4) - sin(t)*sin(pi/4)
= (2sqrt(6)/5)*sqrt(2)/2 - (1/5)*sqrt(2)/2
= 2sqrt(3)/5 - sqrt(2)/10
= %284sqrt%283%29+-+sqrt%282%29%29%2F10