Answer: Let u = ln(x). Then, we have:
y = y(u)
dy/dx = dy/du * du/dx = dy/du * (1/x)
d^2y/dx^2 = d/dx (dy/du * du/dx) = d^2y/du^2 * (1/x)^2 - dy/du * (1/x^2)
Substituting these into the original differential equation yields:
d^2y/du^2 - dy/du + (4 - e^u)y = e^(2u)
This is now a second-order ordinary differential equation in y with constant coefficients, which can be solved using standard methods such as the characteristic equation or undetermined coefficients.
Explanation: