What is wrong in my Fsolve m-file ????

when I saved the m-file below under the name trial.m

function fcns=trial(z)

x=z(1);

y=z(2);

fcns(1)=A.*x.^p1+2.*y.^2-5.*x+7.*y-40;

fcns(2)=3.*x.^2-y.^2+4.*x+B.*y.^p2-28;

end

and when I entered in the command window:

A=1

B=2

p1=2

p2=1

guess=[2 3]

and after that I entered in the command window:

result=fsolve(@trial,guess)

I received the following error message:

??? Undefined function or variable 'A'.

Error in ==> trial at 4

fcns(1)=A.*x.^p1+2.*y.^2-5.*x+7.*y-40;

Error in ==> fsolve at 254

fuser = feval(funfcn{3},x,varargin{:});

Caused by:

Failure in initial user-supplied objective function evaluation.

   FSOLVE 
  cannot continue.

Please what is wrong in my m-file ? ( the same m-file is working when A,B,p1 and p2 are replaced by numbers in the m-file )

I am using m-files like this one because working with x and y for me is easier than working with other names of variables.

Also the m-file must have a name because I need it to use it when I am entering the f-solve command in the command window.

Answer 1

[Walter Roberson]

Variables that you define in the command window become part of the "base" workspace, and are not visible to the workspace of your function.

The fsolve documentation says,

Note: Passing Extra Parameters explains how to pass extra parameters to the system of equations, if necessary.

You should click on that link.

[kamal kiki]

Thanks a million Walter Roberson,the documentation in the link is really helping.