Question 69515: Find the exact value of cos^-1(cos(4pi/3)).
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Find the exact value of cos^-1(cos(4pi/3)).
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You would think the answer was 4pi/3,
but the range of cos^-1 is [0,pi]
The corresponding angle is 2pi/3.
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I think you will find the angle is (2/3)pi or 120 degrees.
Cheers,
Stan H.
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