m=6;
n=7;
a=0;
b=2;
c=0;
d=1;
h1=(b-a)/m;
h2=(d-c)/m;
C=zeros(m-1,m-1);
D=zeros(m-1,m-1);
A=zeros((m-1)*(n-1),(m-1)*(n-1));
F=zeros((m-1)*(n-1),1);
U=zeros((m-1)*(n-1),1);
C(1,1)=2*(1/h1^2+1/h2^2);
C(1,2)=-1/h1^2;
C(m-1,m-1)=2*(1/h1^2+1/h2^2);
C(m-1,m-2)=-1/h1^2;
for i=2:m-2
C(i,i-1)=-1/h1^2;
C(i,i)=2*(1/h1^2+1/h2^2);
C(i,i+1)=-1/h1^2;
end
for i=1:m-1
D(i,i)=-1/h2^2;
end
for i=1:m-1
for j=1:m-1
A(i,j)=C(i,j);
A(i,m-1+j)=D(i,j);
end
end
for i=1:m-1
for j=1:m-1
A((m-1)*(n-2)+i,(m-1)*(n-2)+j)=C(i,j);
A((m-1)*(n-2)+i,(m-1)*(n-3)+j)=D(i,j);
end
end
for r=1:n-3
for i=1:m-1
for j=1:m-1
A((m-1)*r+i,(m-1)*r+j)=C(i,j);
A((m-1)*r+i,(m-1)*(r-1)+j)=D(i,j);
A((m-1)*r&#