Why do i keep getting this," Incorrect use of '=' operator." error?

this is my code:

function z=fxy(M,N)
    z=0;
    for m=1:M & n=0:N
       z = z+ ((10^5)*sin(x*y))+ ((((-1)^m)/(m^3))*(x.^m))+ ((y^n)/(factorial(n)));
    end
    alpha=linspace(-2,2,120);
beta=linspace(0,3,88);


[alpha,beta]=meshgrid(alpha,beta);
Z=fxy(20,25); //the error occurs here. 
what do i do? 

Answer 1

[James Tursa]

This is not valid MATLAB syntax:

for m=1:M & n=0:N

Maybe you wanted nested for loops?

for m=1:M
    for n=0:N
       z = z+ ((10^5)*sin(x*y))+ ((((-1)^m)/(m^3))*(x.^m))+ ((y^n)/(factorial(n)));
    end
end

Where is this function getting x and y from?

[Rafael Hernandez-Walls]

and this part of code:

alpha=linspace(-2,2,120);
beta=linspace(0,3,88);
[alpha,beta]=meshgrid(alpha,beta);
Z=fxy(20,25);

in other file