Hi, I need help with a difficult differential equation. The following is the differential equation for a beam on a varying-stiffness elastic foundation. Essentially the beam sits on a cantilever, whose stiffness varies to the third power with length. Does anybody know how to solve such an equation as a closed form solution (if possible)? E*I*y(x)''''+k*y(x)/x^3=0 where k is a constant.