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Prove that (4 cos^(2)9^(@)-3)(4 cos ^(2)...

Prove that `(4 cos^(2)9^(@)-3)(4 cos ^(2)27^(@)-3)=tan 9^(@)`.

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To prove that \( (4 \cos^2 9^\circ - 3)(4 \cos^2 27^\circ - 3) = \tan 9^\circ \), we will follow these steps: ### Step 1: Use the identity for \( \cos 3x \) We know that: \[ \cos 3x = 4 \cos^3 x - 3 \cos x \] This can be rearranged to express \( 4 \cos^2 x - 3 \): ...
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