6: The limit algebra shows that the answer depends on the number
(a − 1).
There are three possibilities, two of them can be done using the limit
algebra (when a − 1 is positive or negative).
The third, a − 1 = 0,
needs some work, since
∞0
is an indeterminate power. Fortunately, here this can
be worked out just by going back a bit, no tricks are needed.
The answers are:
Answer