Notes: matrix operations

The slides from today, plus two worked examples of multiplying non-square matrices for anyone who wants another pass.

The first example is a 2×3 times a 3×2, which is the shape people get wrong most often. Read the dimensions out loud before you start and the inner numbers have to match, or the product does not exist.

The second example runs the same product the other way round to show that order changes the answer. Matrices are not numbers; you cannot swap them and hope.