I need to find the products of AB and BA, if possible.
Being that both matrices are 4x4's I have concluded that matrix A x B and B x A are both possible. Would appreciate help and an explanation, Thanks!!!
P.S. Sorry if the matrices are sloppy, not entirely sure on how to type an complete solid matrix, sorry!
It is a sure thing that you have been given notes on how to multiply two matrices. Furthermore, there are thousands of websites that explain the process. The formula given above might be too abstract for you to use. In which case, I suggest you use Google to find some worked examples of matrix multiplication.
January 3rd 2011, 09:37 PM
January 4th 2011, 02:15 AM
Have you learned the "dot product" of two vectors- .
If so, the number in the "i,j" place (i th row and jth column) of AB is the dot product of the ith row of A and the jth column of B.
The second row of your A is and the third column of B is . Their dot product is . The number in the second row and third column of AB is 0.
Now, practice! This isn't something you learn in a few minutes.
January 4th 2011, 02:42 AM
The posts above are all very good. I think it might also help if I spell out a couple of the computations for you. I am going to use the method that I think is easiest to understand: