You can put this solution on YOUR website! cos(5pi/8) what is the acute reference angle?
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The reference angle is ALWAYS the angle formed
by the terminal side of the given angle and
the closest segment of the x-axis.
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Your problem:
(5/8)pi is (1/8)pi from the x-axis.
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So the reference angle is (1/8)pi
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Cheers,
Stan H.
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