clearvars; %format long;
prompt1 = 'What is the value of n? '; prompt2 = 'What is the value of delta? ';
n = input(prompt1); delta= input(prompt2); I=eye(n,n); z=rand(n,n);
% disp(' '); disp('If A*x=b where');
A=I+delta*z;
% disp('and');
b=rand(n,1);
tic;
x=A\b;
norm_Method_A = norm(x,2);
t=toc;
fprintf('%s %9.4f %s\n','then using Matlab''s ''backslash'' command, Method A, it requires ',...
    t,'seconds to compute solutions');
fprintf('%s %9.4f\n','for Method A, the 2-norm of vector x =', norm_Method_A);
% for i=1:n;
%     fprintf('%s %i %s %7.5f\n','     x(',i,')=',x(i) );
% end

tic;
x=inv(A)*b;
norm_Method_B = norm(x,2);
t=toc;
fprintf('%s %9.4f %s\n','then using Matlab''s inv(A) command, Method B, it requires ',...
    t,' seconds to compute solutions');
fprintf('%s %9.4f\n','for Method B, the 2-norm of vector x =', norm_Method_B);
% for i=1:n;
%     fprintf('%s %i %s %7.5f\n','     x(',i,')=',x(i) );
% end
tic;
DetA=det(A);
for i=1:n;
    B=A;
    B(:,i)=b;
    x(i)=det(B)/DetA;
end
norm_Method_C = norm(x,2);
t=toc;
fprintf('%s %9.4f %s\n','then using Cramer''s Rule, Method C, it requires ',...
    t,' seconds to compute solutions');
fprintf('%s %9.4f\n','for Method C, the 2-norm of vector x =', norm_Method_C);
% for i=1:n;
%     fprintf('%s %i %s %7.5f\n','     x(',i,')=',x(i) );
% end