$\"\"$

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The trigonometric expression is $\"\"$ .

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Find the value of $\"\"$ .

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Rewrite the expression.

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$\"\"$ .

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Half angle formula: $\"\"$ .

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$\"\"$

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Substitute $\"\"$ .

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$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

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Therefore, $\"\"$ .

\

$\"\"$

\

Find the value of $\"\"$ .

\

Rewrite the expression .

\

$\"\"$ $\"\"$ .

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Half angle formula : $\"\"$ .

\

$\"\"$

\

Substitute $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

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Therefore, $\"\"$ .

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$\"\"$

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$\"\"$ .

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$\"\"$ .