Prove that `(4cos^2 9^0-3)(4cos^2 27^0-3)=tan9^0dot`

Explanation

To prove that

\[ (4 \cos^2 9^\circ - 3)(4 \cos^2 27^\circ - 3) = \tan 9^\circ, \]

we will start with the left-hand side (LHS) and manipulate it step by step.

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