1.

\begin{array}{c}{\frac{\sin A+\cos A}{\sin A-\cos A}+\frac{\sin A-\cos A}{\sin A+\cos A}} \\ {\frac{2}{\sin ^{2} A-\cos ^{2} A}=\frac{2}{2 \sin ^{2} A-1}}\end{array}

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