SOLUTION: How do I use the difference identity to find an exact value for cos(-15). I was able to get the answer of sqrt(6)- sqrt(2) all over 4. But, the correct answer did not subtract th

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Question 546763: How do I use the difference identity to find an exact value for cos(-15). I was able to get the answer of sqrt(6)- sqrt(2) all over 4. But, the correct answer did not subtract the sqrt(2), it added it. I'm not sure what I did wrong! Please help me! Thanks!
Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
How do I use the difference identity to find an exact value for
cos(-15) = -0.7597
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Cheers,
Stan H.
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