Please help for finding 2 Linearly Independent solutions of
x2y'' + xy' + 4y = 0
let y=xA so y' = Ax(A-1) and y'' = A(A-1)x(A-2)
So A(A-1) + A + 4 =0
which is A2 + 4 = 0
A = +/- 2i
then I don't know how to find 2 LI solutions, please help..