Let me explain why it is obvious. The thinking process is like this: the top is n power, and the bottom is n power. When n approaches infinity, it will converge, so how many powers of n can't be infinite? Then only an infinite power less than 1 can converge.

Below n, above n power, if it is to converge, it is only less than 1. If it is greater than 1, it must be infinite when it is infinite above. Experience in calculation, feeling of series calculation.