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Is it possible for an even function to have the entire set of real numbers as the range? I thought much about it but I didn't find. Please explain if anybody knows.

Waqar
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2 Answers2

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Take $f(x)=x\sin x$ as what you want!

Mostafa Ayaz
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How about $x^{2m} \cos(nx)$ a bit of generalization I think.

egreg
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Devendra Singh Rana
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