$\"\"$

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The angle of elevation is $\"\"$ .

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From the trigonometric identity : $\"\"$ .

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Observe the figure :

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

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Substitute all the above values in $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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

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$\"\"$

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