SOLUTION: Find the exact value of cos225� using 2 different formulas. Please note: I tried using both the double and half angle formulas but I can't seem to get the answer. Your help woul

Question 867731: Find the exact value of cos225� using 2 different formulas.
Please note: I tried using both the double and half angle formulas but I can't seem to get the answer. Your help would be greatly appreciated. With detailed steps so I can learn from it too. Thanks!
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!

Find the exact value of cos225� using 2 different formulas.
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Use cos(225) = -cos(45)
AND
Use cos(225) = cos(180+45)
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Cheers,
Stan H.
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