1) It doesn't refer to A, it refers to the rows in B. (It must, because it's part of a subscripting expression for B). It has to be the same length of size(A,1) in order for the assignment to be conformant; otherwise you'd have a size mismatch.
2)
a) A*ind2 is the product of a vector by single value. Matlab does that automagically as part of the syntax of "vectorized" array calculations.
b) No, the problem statement says to make the subsequent columns the value of the first column times the column number. That's what the loop is building.
c) "=" is the assignment operator -- it assigns the RHS to the LHS target (in this case the subsequent columns of B)
In your case, you're trying to append all three columns at once but each pass thru the loop your x is one value as you overwrite the previous value of x from the subsequent loop each time thru.
A somewhat more "Matlab-y" solution could look something like
A=rand(10,1); % credit to the student, you found that one--good job!!
B=zeros(length(A),4); % preallocate so don't "grow" the array dynamically
for ii=1:4
B(:,ii)=A*ii;
end
This eliminates the specific "magic number" row indices but still uses a loop. As you progress you'll learn ways to eliminate the loop entirely.
I suggest working thru the "Getting Started" section in the online documentation--it shows all of these things and more in introducing you to Matlab.
