A classical math problem: differential equations

Here is the Mathcad 11 sheet that solves nth order differential equations with constant coefficients, referenced in the document thread with similar name here: A Classical Math Problem from a Classical Text (Differential Equation).

Note that this, as it is, is NOT usable for:
- Systems of differential equations,

- Differential equations where the coefficients of the derivatives are not constants (when they depend on t).

But in both cases, similar techniques can be used to solve specific systems.

Luc