SOLUTION: please help me solve this: sin^2 2pi/5 - cos^2 2pi/5

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Question 238105: please help me solve this: sin^2 2pi/5 - cos^2 2pi/5
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


I'm not sure what you mean by "solve this." There is no equals sign and no variable.

The only thing I can think to do with this is to calculate a numerical approximation. First recognize that:



Therefore



hence



But not sure where you want to go from here.


John