matrix entry into function

In a matrix A, I have assinged x(t)=A(t,2)

But if I want to calculate x(t+1)-x(t), it returns an error. How can I fix? Matlab doesn't specify which error I have made.

+ is it possible that I write a function and when I execute it it returns a message with enter "t" so I don't have to rewrite the code for different t? I think I did something similar in python or some other language but I'm not sure with matlab.

[KSSV]

Show us your code. Or how A is related to t.

Answer 1

[Cris LaPierre]

Also, share the complete error message (all the red text),

My suspicion is that x(t+1) does not exist.

x=1:5;
t=5;
x(t+1)-x(t)

Index exceeds the number of array elements (5).