[求助]程序出错了，恳请大家帮帮忙

[小翠鸟]

这是程序，调用函数是教材上的，应该没问题。我这里用到了符号计算，但怎样把符号表达式传递给调用函数呢？:cry:
syms x y
m=2
h=0.0003;
w=0.0005;
a=0.0001
e=h/w
for i=1:m
z1=cos((2*i-1)/2*pi.*x).*sin((2*i-1)/2*pi.*y)
for j=1:m
z2=cos((2*j-1)/2*pi.*x).*sin((2*j-1)/2*pi.*y)
z1x=diff(z1,x)
z2x=diff(z2,x)
z1y=diff(z1,y)
z2y=diff(z2,y)
ff=e^2*z1x.*z2x+z1y.*z2y
c(i,j)=double_in(ff,0,@y_hi,0,1)
end
end
matlab 给出的错误
??? Error using ==> fcnchk
If FUN is a MATLAB object, it must have an feval method.

Error in ==> quad at 55
f = fcnchk(funfcn);

Error in ==> G_yi at 11
f(i)=quad(fp,yy1(i),yy2(i),[],[],x(i));

Error in ==> quad at 62
y = f(x, varargin{:});

Error in ==> double_in at 8
ss=quad(@G_yi,x1,x2,[],[],y1,y2,fp);
Error in ==> fp1 at 17
c(i,j)=double_in(ff,0,@y_hi,0,1)