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Limitation of -4 to the left of the absolute value of x+4 divided by x+4

User Estn
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1 Answer

20 votes
20 votes

I believe you're asking about the one-sided limit,


\displaystyle \lim_(x\to-4^-)(|x+4|)/(x+4)

Recall the definition of absolute value:


|x| = x if
x\ge0


|x| = -x if
x < 0

Since we're approaching -4 from the left, we're effectively focusing on a domain of
x<-4 or
x+4<0. So, by the definition above, we have
|x+4| = -(x+4). Then in the limit, we have


\displaystyle \lim_(x\to-4^-)(|x+4|)/(x+4) = \lim_(x\to-4^-)(-(x+4))/(x+4) = \lim_(x\to-4^-)(-1) = \boxed{-1}

User Spease
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