In an assignment A(I) = B, the number of elements in B and I must be the same.

why is this giving an error...!

A1=[2 1];
>> for i=1:2;
A(k)=[-1 1];
A(k+1)=A1+A(k);
end

[Al Capwn]

because A1+A(k) has dimensions 1x2 where as A(k+1) has dimensions 1x1.

A1+A(k)

is interpreted as

   [A1(1)+A(k) A1(2)+A(k)].

Answer 1

[Thorsten]

You cannot assign a 1x2 matrix [-1 1] to a single element A(k) of a matrix.

It is not clear to me what you want to achieve with these lines. Note that your loop uses i, but i is never used in the loop.

Answer 2

[Eng. Fredius Magige]

A1=[]; >> for i=1:2; i=i A1(1,1)=i.*-1 A1(1,2)=1 %k==i, you mean that A1=[A1; []] % or you mean this A1' end