Problems with the ode solvers

 I have been trying to write programs for solving simple, linear second-order ode's using ode45. I have managed to write working programs for first-order ode's, but my attempts at programs for second-order ode's have error messages I cannot understand.
 Are there examples, complete code, for solving linear, second-order ode's? If so, where can I find them. (The code for the example given in the text, the van der Pol's equation, is split into different parts and is confusing when I try to use it.)

[Jan]

It would be helpful, if you post your code and the error messages. Then a suggestion for improvements would be much easier.

Answer 1

[Azzi Abdelmalek]

Look at this answer