Question #1488e

1 Answer
Oct 8, 2017

The limit does not exist.

Explanation:

We can't simply plug in #x=2#, because this will give us a denominator of #0#.

However, note that at #x=2#, the term #x^(1/3) - 2# will NOT be #0#.
Instead, it will be #2^(1/3) - 2#, which is less than #0#.

Let's approach #x=2# from both sides:

Let #x = 2 + a#, where #a# is an extremely small number. Then the negative limit is:

#lim_(a->0^-)((2+a)^(1/3)-2)/a = "negative value"/"negative value approaching 0" = "positive value"/"positive value approaching 0" = oo#

Similarly, the positive limit is:

#lim_(a->0^+)((2+a)^(1/3)-2)/a = "negative value"/"positive value approaching 0" = -oo#

Since the negative limit is #oo# and the positive limit is #-oo#, the two limits are not the same and therefore we say the limit does not exist.

To show this limit, here is the graph of the function #y = (x^(1/3)-2)/(x-2)#
graph{(x^(1/3)-2)/(x-2) [-3.184, 6.816, -2.32, 2.68]}

Final Answer