6: We should start by noting that no (real) value of a will cause trouble in the limit, so the question makes sense for all values of the parameter.

After substituting in the limit point you should get

This looks like "zero over zero", but one has to be careful. If a = 0, we get an indeterminate power in the numerator. Since this is a special value of parameter, this case is best handled by going back to the given limit. Otherwise we have a standard case for l'Hospital's rule.

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