For any triangle, show that cos(Y/2) = sqrt{[2(2 - c)]/(ab)} where s = (a + b + c). Hint Given: Use the Half-angle Formula and the Law of Cosines.
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Originally Posted by magentarita Use the Half-angle Formula and the Law of Cosines. Why do you post if you know what to do ?
Last edited by Moo; September 14th 2008 at 09:06 AM.
Originally Posted by magentarita For any triangle, show that cos(Y/2) = sqrt{[2(2 - c)]/(ab)} where s = (a + b + c). Hint Given: Use the Half-angle Formula and the Law of Cosines. I'll bite. What's Y? And where does the s come into the equation? -Dan
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