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The solution of the differential equation $\frac{d^2y}{dt^2} + 2 \frac{dy}{dt}+y=0$ with $y(0)=y’(0)=1$ is

1. $(2-t)e^t$
2. $(1+2t)e^{-t}$
3. $(2+t)e^{-t}$
4. $(1-2t)e^t$