Plot det(matrixA - (x * eye(3))) where x = 0:3

I am new to MatLab and have been searching for a way to do plot this graph but cannot seem to figure it out.

Equation: det(matrixA - (x * eye(3))) where x = 0:3 and Matrix A is a predefined matrix

Error: Error using * Inner matrix dimensions must agree.

t = 0:3 Error in y1 = det(A1 - (t * eye(3)))

This equation as it stands is giving me an error everytime I run it and i think i understand where its coming from but am unsure how else to go about writing the equation any other way. I also need to be able to plot this for 4 different matrix A's on the same plot. Any help would be really appreciated! Thanks.

Answer 1

[Walter Roberson]

   matrixA = rand(3); % do for some random matrix A

   syms x
   matdet = det(matrixA - (x * eye(3)));
   fplot(matdet, [0 3])

[Andrew Gapinski]

Thanks for the quick response, I tried running this and am getting this error: Invalid indexing or function definition. Indexing must follow MATLAB indexing. Function arguments must be symbolic variables, and function body must be sym expression.

[Andrew Gapinski]

Nvm a simple clearvars worked. Thanks!