How to use numerical solution in differential equation?

I have numerical solution for variable p, which I got through ode45 method. I need to calculate u, where

u=((r^2-1)/16)*dp/dz

May I use my numerical solution for p and calculate dp/dz in second equation? Is it possible in matlab and on which way?

Answer 1

[Torsten]

Use MATLAB's "diff" on the array of p-values to approximate dp/dz:

https://de.mathworks.com/help/matlab/ref/diff.html

Best wishes

Torsten.