Originally Posted by

**kenny** Thanks for your fast response.

I'm still not quite sure how I am going to set it up. I have found the piece of paper with my supervisors hints. He does this:

$\displaystyle x'' + 5x' + 6x = 0$

$\displaystyle x_1 = x, x_2 = x'$

$\displaystyle x_1' = x_2, x_2' = x'' = -5x_2 -6x_1$ (which is what you said basically)

and sets up x' = Ax, which has solution $\displaystyle e^(At)x_0$

This is the analytical solution and I understand it, but I'm kind of confused on the numerical methods way of doing it.

I think its meant to be RK4 on $\displaystyle x_1' = x_2$ and then on $\displaystyle x_2' = -5x_2 -6x_1$, but what do I do with these two outputs?

I'm fairly sure the original equation is only meant to have 1 output.