Problem: Find the leading order WKB approximation for the specific differential equation: $\epsilon^2 y'' + \cosh(x) y' + \sinh(x) y = 0$ with initial conditions at $y(0) = 0$, $y(1) = 1$. where $\epsilon$ is a small positive parameter ($0 < \epsilon \ll 1)$. Give your final answer in a \boxed latex environment.
Solution: $\boxed{y(x) = \cosh(1)(\frac{1}{\cosh(x)} - \cosh(x) e^{-\sinh(x)/\epsilon^2}) }$