SOLUTION: if 8x=pi then show that cos7x + cotx =0

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Question 984776: if 8x=pi then show that cos7x + cotx =0
Answer by ikleyn(52879) About Me  (Show Source):
You can put this solution on YOUR website!

If 8x = pi then show that cos%287x%29 + cot%28x%29 = 0.
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I think it is WRONG.

Indeed,  x = pi%2F8.

cos%287x%29 = cos%287pi%2F8%29 = -cos%28pi%2F8%29.

The statement is   -cos%28pi%2F8%29 + %28cos%28pi%2F8%29%29%2F%28sin%28pi%2F8%29%29 = 0 ?

It is WRONG.