Prove that `1/(secA-tanA)-1/(cosA)=1/cosA-1/(secA-tanA)`.

Explanation

To prove that

\[ \frac{1}{\sec A - \tan A} - \frac{1}{\cos A} = \frac{1}{\cos A} - \frac{1}{\sec A - \tan A} \]

we will start by simplifying the left-hand side (LHS) and the right-hand side (RHS) separately.

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