SOLUTION: What is the exact value of cos205 degrees?

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Question 935737: What is the exact value of cos205 degrees?
Answer by MathLover1(20855) About Me  (Show Source):
You can put this solution on YOUR website!
205 degrees is 180 degrees + 25 degrees, we can write cos as cos%28205%29=cos%28180%29cos%2825%29
cos%28205%29=cos%28180%29cos%2825%29=-1%2A0.906307787=-0.906307787
or, we can use only -cos%2825%29 (it is cos%2825%29 in III quadrant because 205 degrees angle is in that quadrant)

cos%28205%29=-cos%2825%29=-0.906307787