$\"\"$

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The expression is $\"\"$ .

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$\"\"$ (Apply Pythagorean identity)

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$\"\"$ (Subtract $\"\"$ from each side)

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$\"\"$ (Simplify)

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$\"\"$ (Substitute $\"\"$ )

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$\"\"$ (Evaluate power: $\"\"$ )

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$\"\"$ (Subtract: $\"\"$ ) $\"\"$

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$\"\"$ (Take the square root of each side)

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$\"\"$ (Simplify)

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$\"\"$ is in the first quadrant, sin $\"\"$ is positive,

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Therefore $\"\"$ .

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$\"\"$ (Apply quotient identity) \ \

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$\"\"$ (Substitute $\"\"$ and $\"\"$ )

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$\"\"$ (Divide: $\"\"$ ) \ \ $\"\"$

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The value of $\"\"$ .