SOLUTION: Find the exact value of cos315 degrees

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Question 149724: Find the exact value of cos315 degrees
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
315 degrees is 45 degrees away from 0 degrees.
Therefore sin(315)=cos(315).
You also know that for any angle, x,
sin%5E2%28x%29%2Bcos%5E2%28x%29=1
In this case,
cos%5E2%28315%29%2Bcos%5E2%28315%29=1
2cos%5E2%28315%29=1
cos%5E2%28315%29=1%2F2
cos%28315%29=1%2Fsqrt%282%29
cos%28315%29=sqrt%282%29%2F2