Input argument "U" is undefined.

Hi everyone! I don't know what to do with this error. I've tried so many times.

I know it's a very simply case, but I'm new to Matlab.

This is my code.

function Y=fpendolo(U)

u=U(1);

x1=U(2);

x2=U(3);

and everytime it says ''??? Input argument "U" is undefined.

Error in ==> fpendolo at 10

u=U(1);''

Thanks everyone!

Answer 1

[David Hill]

U=1:3;%setup variable
[u,x1,x2]=fpendolo(U);%call function

function [u,x1,x2]=fpendolo(U)
  u=U(1);
  x1=U(2);
  x2=U(3);
end