1-12 PDEs SOLVABLE AS ODEs. This happens if a PDE involves derivatives with respect to one variable only (or can be transformed to such a form), so that the other variable(s) can be treated as parameter(s). Solve for u = u(x, y):
1. uyy + 16u = 0
2. uxx = u
3. uyy = 0
4. uy + 2yu = 0
5. uy + u = exy
6. uxx = 4y^2u
7. uy = (cosh x)yu
8. uy = 2xyu
9. y^2uyy + 2yuy - 2u = 0
10. uyy = 4xuy