This week I am going to teach some more about Matrices.

Since we did addition last week, we are going to move up to multiplication.

The first thing you need to know about multiplying matrices is when looking at dimensions of the two you are trying to multiply B and C MUST be the same number.

You use the term AxB CxD to check for this.

When multiplying, you multiply each number in the first matrix’s row by each number in the second matrix’s column.

After doing this you will add the numbers from which you multiplied each row by column.

The rows and columns that you multiply is going to be where you place the number in the answer matrix.

Now for an example of how to multiply matrices:

Example 1:

[1 2 3 -2] X

2

0

-1

3

1(2)=2

2(0)=0

3(-1)=-3

-2(3)=-6

So you answer matrix is going to be,

2 0

-3 -6

Hope you learned how to multiply matrices!

---Carley :)