Lim ato0 (a+x)^3/a ?

1 Answer
Apr 5, 2018

The limit #lim_(a->0) (a+x)^(3/a) # does not exist.

Explanation:

I will assume the limit to be: #lim_(a->0) (a+x)^(3/a) #

First, consider that #a-> 0^+# then #3/a# increases beyond all bounds.

Thus #lim_(a->0^+) (a+x)^(3/a) -># x raised to positive infinity.

#:. if absx> 1 -> lim_(a->0^+) (a+x)^(3/a) = +oo#

and # if absx< 1 -> lim_(a->0^+) (a+x)^(3/a) = 0#

also, #if x={0,1} ->lim_(a->0^+) (a+x)^(3/a)# is undefined.

We can also analyse the limit as #a->0^-#

In this case #lim_(a->0^-) (a+x)^(3/a) -># x raised to negative infinity.

#:. if absx> 1 -> lim_(a->0^-) (a+x)^(3/a) = 0#

and # if absx< 1 -> lim_(a->0^-) (a+x)^(3/a) = +oo#

again, #if x={0,1} ->lim_(a->0^-) (a+x)^(3/a)# is undefined.

So we can see that the limit yields different results as #a# approaches #0# from above or below for all #x# where the limit is defined.

Hence, the limit does not exist.