For the people who are interested in ML, the thing to remember here is that he is a Serious mathematician, and he values rigor and in-depth understanding above all. A lot of his three star homework problems were basically impossible. He writes books first and foremost so he can understand things better. In math books, there's the book you first read when you don't understand something, then the book you read when you understand everything. This is book in the link.
for linear algebra, this:https://www.amazon.com/Introduction-Linear-Algebra-Gilbert-S...)
What he does with chalk and a blackboard is far more effective than anything done today with Powerpoint, fancy computer animations, or what have you.