SOLUTION: Let x=cos72° - cos36°. Find the value of x^-4 in simplified form.

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Question 659780: Let x=cos72° - cos36°. Find the value of x^-4 in simplified form.
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

x=cos72+-+cos36

Find the value of x%5E-4
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x=cos72+-+cos36
x=%281%2F4%29%28-1-%281%2Fsqrt%285%29%29%29+%2B+%281%2F4%29%28sqrt%285%29-1%29=-0.5
%28-0.5%29%5E-4
1%2F%28-0.5%29%5E4
1%2F0.0625
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