resolehtmai1 wrote:In this question, why are we neglecting the possibility that n could be negative?From \((9)^1 + (99)^2 + (999)^3 + ... + (10^n - 1)^n\) it follows that n is an integer more than or equal to 1.Check here: m10-36-isn-t-ambiguous-86861.html#p981080 _________________