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Definition of even function :

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If $\"\"$ is an even function, then $\"\"$ .

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Check the options one by one.

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(A). The function is $\"\"$ .

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

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$\"\"$

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$\"\"$

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Since $\"\"$ , $\"\"$ is not even function.

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(B). The function is $\"\"$ .

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

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$\"\"$

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$\"\"$

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Since $\"\"$ , $\"\"$ is an even function.

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(C). The function is $\"\"$ .

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

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$\"\"$

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$\"\"$

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Since $\"\"$ , $\"\"$ is not even function.

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(D). The function is $\"\"$ .

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

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$\"\"$

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$\"\"$

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Since $\"\"$ , $\"\"$ is not even function.

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$\"\"$ is an even function.

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Option (B) is correct.

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Option (B) is correct.