ex_9

A=[1 2 3; 2 2 2; -1 2 1];
B=[1 0 0; 1 1 0; 1 1 1];
C=[1 1; 2 1; 1 2];

% Part (a)
A+B
A*B
A+C %error because dimensions of A and C do not match
B*A
B-A
A*C
C-B %error because of dimension of C and B do not match
C*A %error because C and A are incompatible for matrix multiplication

%Part (b)
%{
The difference between A*B and A.*B is that A*B is the usual
matrix multiplication and on the other hand, A.*B is element
wise matrix multiplication.
It is possible to compute A*B if number of columns of A = number of rows of B.
On the other hand, it is possible to compute A.*B if the dimensions of A and B are the same.
%}
A.*B