Matlab Matrix Help Needed on Annotation

Hi guys, i need help on the annotation of the 4 annotate required field, my lecturer just threw these to us when we are not taught how to program in matlab =(( .

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Appendix A: Code for Assignment Question 3

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function x = Gauss(A, b)

% Solve linear system Ax = b

% using Gaussian elimination without pivoting

% A is an n by n matrix

% b is an n by k matrix (k copies of n-vectors)

% x is an n by k matrix (k copies of solution vectors)

[n, k] = size(b); % Annotate this

x = b; % Annotate this

for i = 1:n-1

    m = -A(i+1:n,i)/A(i,i); % Annotate this

    A(i+1:n,:) = A(i+1:n,:) + m*A(i,:); %Annotate this

    b(i+1:n,:) = b(i+1:n,:) + m*b(i,:);

end;

% Use back substitution to find unknowns

x(n,:) = b(n,:)/A(n,n);

for i = n-1:-1:1

    x(i,:) = (b(i,:) - A(i,i+1:n)*x(i+1:n,:))/A(i,i);

end

Answer 1

[Walter Roberson]

I think "annotate" here means "explain this in a comment".

http://www.mathworks.com/matlabcentral/answers/8026-best-way-s-to-master-matlab

[Stanley]

yeah, but i dont understand the codes

[Walter Roberson]

http://www.mathworks.com/help/matlab/math/matrix-indexing.html