Prove that: `(cos(pi+x)cos(-x))/(sin(pi-x)cos(pi/2+x))=cot^2x`

Explanation

To prove that

\[ \frac{\cos(\pi + x) \cos(-x)}{\sin(\pi - x) \cos\left(\frac{\pi}{2} + x\right)} = \cot^2 x, \]

we will simplify the left-hand side step by step using trigonometric identities.

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