Consider a system governed by the following equations $$\frac{dx_1(t)}{dt} = x_2(t)-x_1(t) \\ \frac{dx_2(t)}{dt} = x_1(t)-x_2(t)$$ The initial conditions are such that $x_1(0)<x_2(0)< \infty$. Let $x_{1f}= \underset{t \to \infty}{\lim} x_1(t)$ and $x_{2f}=\underset{t \to \infty}{\lim} x_2(t)$. Which of the following is true?
1. $x_{1f}<x_{2f}<\infty$
2. $x_{2f}<x_{1f}<\infty$
3. $x_{1f}<=_{2f}<\infty$
4. $x_{1f}=x_{2f}=\infty$