I am emailing a link of this to everyone on the class list every Friday afternoon. If you are not receiving these emails or want to have them sent to another email address feel free to email me at jpmccarthymaths@gmail.ie and I will add you to the mailing list.

## Week 3

We learned how to use the matrix inverse to solve simultaneous equations. We also introduced Cramer’s Rule which is a method that is useful if you only want to find one of the variables rather than all of them. Cramer’s Rule uses determinants and we showed how to calculate the determinant of $2\times 2$ and $3\times 3$ matrices. We also explained that when the determinant of the coefficient matrix is zero, the Gauss-Jordan algorithm cannot work because the matrix is not invertible.

## Week 4

In Week 4 we will begin our study of Vector Algebra.

## Tutorials

If we can do the question on page 43 of the notes, then you are in a good place for matrix algebra. I have made a promise that I will make the matrix inverse easier to compute like the examples on p.22 and 23.