Since you are defining your function as having a input x, you do not need to redfine it within your function. You can also achieve what you are asking without having to create any functions since max and min are already built-in to MATLAB, which brings up another point of what to avoid. You should try to stay away from using variables that are already defined as functions.
Unless there is any reason that you need x and y to be 10x10 arrays it would make the use of max and min simplier if you make x and y vector-arrays with 100 elements.
x = randi([-9999,9999],100,1);
y = 2.5+rand([100,1]);
minX = min(x);
maxX = max(x);
minY = min(y);
maxY = max(y);
If you need to create a function to accomplish this task, try the following. It will also easily handle array inputs as well as vectors.
function [Min, Max] = MinMax(value)
Min = min(value(:));
Max = max(value(:));
end
Do the following to use your this function.
x = randi([-9999,9999],10,10);
y = 2.5+rand(10);
[minX, maxX] = MinMax(x);
[minY, maxY] = MinMax(y);
Best Answer