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The function is $\"\\lim_{x\\rightarrow1^-}f(x)=3\"$ and $\"\\lim_{x\\rightarrow1^+}f(x)=7\"$ .

$\"\\lim_{x\\rightarrow1^-}f(x)=3\"$ :

As $\"x\"$ approaches to $\"1\"$ from left side, $\"f(x)\"$ approaches to $\"3\"$ .

$\"\\lim_{x\\rightarrow1^+}f(x)=7\"$ :

As $\"x\"$ approaches to $\"1\"$ from right side, $\"f(x)\"$ approaches to $\"7\"$ .

Here left hand limit and right limit are not equal.

So $\"\\lim_{x\\rightarrow{1}}f(x)\"$ does not exist.

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$\"\\lim_{x\\rightarrow{1}}f(x)\"$ is does not exist.