Which function is a solution to d2ydx2+y=0\frac{d^2y}{dx^2} + y = 0dx2d2y+y=0?
y=sin(x)y = \sin(x)y=sin(x)
y=cos(x)y = \cos(x)y=cos(x)
y=exy = e^xy=ex
y=x2y = x^2y=x2