Could anyone please help me to do matrix multiplication with respect to the sample data given below.

Question

jaah navi 2020-2-21

关闭： MATLAB Answer Bot 2021-8-20

If 
A=[2 3 4] 
B=A*[1;
     2;
     3]

so i want to multiply 2 with

    [1;
     2;
     3]

followed by 3 with

     [1;
     2;
     3]

finally 4 with

    [1;
     2;
     3]

so at the end i need to have 3x3 matrix.

Answer 1

Sindar 2020-2-21

Matrix multiplication only works when the "middle" dimension matches ( N x M ) * ( M x O )

Check the sizes of your matrices:

>> size(A)
ans =
     1     3
>> size([1;2;3])
ans =
     3     1

So, A*([1;2;3]) is not valid, but ([1;2;3])*A is (and gives you what you want):

>> B = [1;2;3]*A
B =
     2     3     4
     4     6     8
     6     9    12