$\"\"$

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The expression is $\"\"$ .

\

Rewrite the expression.

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$\"\"$ .

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Apply sum rule of tan function : $\"\"$

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$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Therefore, the exact value of the expression is $\"\"$ .

\

$\"\"$

\

The exact value of the expression is $\"\"$ .