Problem: Find a uniformly valid leading order approximation to the solution of $\epsilon y'' + x y' + x y = 0$ with boundary conditions $y(-1) = 1$, $y(1) = 2$ in the limit $\epsilon \to 0^+$. Use only the variables and constants given in the problem; do not define additional constants. Place your final solution in a $\boxed{}$ LaTeX environment
Solution: $\boxed{y = e^{-(x+1)} \frac{1-\text{erf}(x/\sqrt{2\epsilon})}{2} + 2e^{1-x} \frac{1+\text{erf}(x/\sqrt{2\epsilon})}{2}}$