14-1

14-1 Matrices
So, I definitely almost forgot about my blog. In this section, we learn how to add and subtract matrices. We also learn how to do scalar multipication. You will also be given directions to transpose matrices. Here are some rules for this section:

• When adding or subtracting matrices, the matrices must have the same dimensions. NO EXCEPTIONS!


• To add/subtract matrices, all you do is add/subtract correspoding entries.


• To use scalar mutipication, all you do is multiply every entry by the number outside the matrices.


• When you are given directions to transpose a matrices, you will see A^t. All you have to do is switch the rows and the columns

Example 1: [3 4 -1] + [6 -3 2] = [9 1 1]

-Add 3 and 6, 4 and -3, -1 and 2, then you get [9 1 1]

Example 2: 4[2 1 6 -3] = [8 4 24 -12]

-Multiply 4 by 2, 1, 6, and then -3, and you get [8 4 24 -12]

Example 3: A = [4 2 6 1] B = [8 4 -2 5]; Find 2A - B.

-2[4 2 6 1] - [8 4 -2 4] = [-8 -4 -12 -2] - [8 4 -2 4]

= [-16 -8 -10 -6]