SOLUTION: Prove that cos35 + cos45 + cos75 + cos85 = 2cos5cos20
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Question 1137787: Prove that cos35 + cos45 + cos75 + cos85 = 2cos5cos20
Found 2 solutions by MathLover1, Alan3354:
Answer by MathLover1(20850) (Show Source): You can put this solution on YOUR website!
prove that
=> statement is (the two sides are not equal)
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
Using a calculator, they are equal.
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I don't plan to do any more on this one.
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