%Script file for Exam 1.  Save this file as exam1matrixA.m

%Run exam1matrixA to obtain the matrix A and vector b
%  then use Jacobi iteration to solve Ax=b so that the
%  estimated b is within 10^-6 of the real b.
%  Save your solution in x by typing:  save exam1x x
%Then email me your script and exam1x.mat

A=zeros(80,80);

for i=1:80
    for j=1:80
        if j==i
            A(i,j)=2*i;
        elseif j==i+2 & i<=78
              A(i,j)=0.5*i;
        elseif j==i-2 & i>=3
              A(i,j)=0.5*i;
        elseif j==i+4 & i<=76
              A(i,j)=0.25*i;
        elseif j==i-4 & i>=5
              A(i,j)=0.25*i;
        end
    end
end

b=pi*ones(80,1);
clear i j