If y(x)=∑n=0∞anxny(x) = \sum_{n=0}^{\infty} a_n x^ny(x)=∑n=0∞anxn satisfies y′′+xy′+y=0y'' + xy' + y = 0y′′+xy′+y=0 with initial conditions y(0)=1y(0) = 1y(0)=1 and y′(0)=0y'(0) = 0y′(0)=0, what is a2a_2a2?
−1-1−1
−12-\frac{1}{2}−21
000
12\frac{1}{2}21