SOLUTION: what is the exact value of cos7pi/4

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Question 700525: what is the exact value of cos7pi/4
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+cos%28+7%2Api%2F4+%29+
Note that +8%2Api%2F4+ is a rotation back
to zero degrees, and +7%2Api%2F4+ is a
45 degree rotation clockwise from 0 degrees
The cosine in the 4th quadrant is (+), so
+cos%28+7%2Api%2F4+%29+=+1+%2F+sqrt%282%29+