## Matlab I am trying to write a function on an M-file

Hi All

I am new with Matlab

I am trying to write a function on an M-file; here is the script:

function f = ali(x)
f = - x(1) * x(2);
A = [-1 -2 -2; 1 2 2]
b = [0; 72]
x0 = [10; 10; 10];
[x,fval] = fmincon(@ali,x0,A,b)

Whenever i run it i get the following message;
input argument "x" is undefined

So can anybody help

Best Regards
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 Recognitions: Gold Member you have to define x when you call the function. How are you running the function? I would suggest using the command window and calling it with: f = ali(x) where x is whatever two numbers you want it to be. in your second line, you call x(1) and x(2) so there has to be two elements in x so at your command window, you could enter: f = ali([5 7]) where I've chosen 5 and 7 arbitrarily.