For this quiz, "Power series" implies that every exponent is a non-negative integer. L.I. means "linearly independent". Some questions refer to -
DE #1 : (x-1)y ' ' + xy ' + y/x = 0
DE #2 : x2y ' ' - xy ' - (x2+5/4)y = 0
Fact: x = 0 is a regular singular point of DE #2, and the indicial equation has roots 5/2 and -1/2.