SOLUTION: I have the question for my math homework right now of "use identities of sine and cosine to find the value of theta given that cosine2theta=3/4, theta therminates in quadrant III."

Question 765492: I have the question for my math homework right now of "use identities of sine and cosine to find the value of theta given that cosine2theta=3/4, theta therminates in quadrant III." I am unsure how to answer this.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
use identities of sine and cosine to find the value
of theta given that cosine(2theta) = 3/4, theta terminates in quadrant III
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Take the cos^-1 of each side to get:
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2theta = cos^-1(3/4) = 41.41 or 41.41+360 = 401.41 degrees
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Then theta = 200.7 degrees
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Cheers,
Stan H.
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