$\"\"$

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The expression is $\"\"$ .

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Let $\"\"$ , then $\"\"$ .

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$\"\"$

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$\"\"$

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Consider $\"\"$ .

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Phytagorean theorem : $\"\"$

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$\"\"$

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$\"\"$

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$\"\"$ .

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$\"\"$

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Substitute $\"\"$ in equation $\"\"$ .

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$\"\"$

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$\"\"$

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The value of $\"\"$ is $\"\"$ .