Error: File: Lab1.m Line: 81 Column: 1 Function definitions in a script must appear at the end of the file. Move all statements after the "f" function definition to before the first local function definition.
What you have shared looks good, but you have not shared your full file (we do not see 81 lines, nor do we see a function f). As the error message states, and declared functions must be at the very bottom of your live script. I suspect there is at least a Question 7 that you have not included, meaning function z is not the last thing in your file.