How can I set variables for a function and then plot the results of the function vs the variable

I am investigating the trace of a matrix, I wish to change some parameters (x and z) in the matrix and from there I want to calculate the eigenvalues and then sum the eigenvalues together to get the trace. I am thinking of creating a characteristic polynomial for my matrix A and then solving the characteristic polynomial for the eigenvalues. Then I will sum the eigenvalue vector to get the trace. How can I change the values of the x and z parameters in my matrix in matlab and then how can I create a plot where the trace is on one axis and the value of the variable parameter is on the other?

[Uday Pradhan]

Hi,

Could you elaborate on what kind of matrix are you dealing with? Are "x" and "z" variable elements of the matrix? Something like

A = [1 x
    23 z];

This might be of help to you : Generalized matrix with tunable parameters