I'm trying to create a MATLAB program that solves a system of first order differential equations using Runge-Kutta method. This is what I have so...

k1z2 = fz2(t(i), z1(i), z2(i));end

So far I only tried to find both k1's to see if the program was working and when I tried to run it I got an error saying "Index exceeds matrix dimensions".

z1 and z2 are two first order differential equations that I got from the original second order differential equation my" + by' + Ky = 0