Question 1: dividing the √x+y on the right to the left is actually parameter separation. Then put all the scores on the left into the root sign, take a "1" on the numerator of the scores in the root sign, and then use the basic inequality to find the maximum value. The minimum value of a is this maximum value.

The second problem: discuss the odd and even numbers of n points, then separate A and N, and establish the problem by using constants, only considering the maximum and minimum values, and pay attention to the reasonable deformation of the score.