How do you find the limit of |x+2| / (x+2)|x+2|x+2 as x approaches -22?

1 Answer
Apr 16, 2016

The limit does not exist.

Explanation:

The absolute value function abs(x+2)|x+2| can be defined as the piecewise function

abs(x+2)={(x+2,;,x>=-2),(-(x+2),;,x<-2):}

We should determine if the limit from the left approaches the limit from the right.

Limit from the left:

When the function is directly to the left of x=-2, we are on the -(x+2) portion of the piecewise function since x<-2.

Thus, the function when x<-2 becomes

abs(x+2)/(x+2)=(-(x+2))/(x+2)=-1

Hence the limit from the left is

lim_(xrarr-2^-)abs(x+2)/(x+2)=lim_(xrarr-2^-)-1=-1

Limit from the right:

From the right, x> -2, so we just use x+2 in place of abs(x+2).

The function becomes

abs(x+2)/(x+2)=(x+2)/(x+2)=1

So the limit from the right is

lim_(xrarr-2^+)abs(x+2)/(x+2)=lim_(xrarr-2^+)1=1

Relating the limits:

Since lim_(xrarr-2^+)abs(x+2)/(x+2)!=lim_(xrarr-2^-)abs(x+2)/(x+2), we know that lim_(xrarr-2)abs(x+2)/(x+2) does not exist.

In fact, we saw that the function is simply y=-1 when x<-2 and is y=1 when x> -2.

Graphed is abs(x+2)/(x+2):

graph{abs(x+2)/(x+2) [-13.77, 8.73, -5.62, 5.63]}