[NationalPark]

Many of the suggestions so far are assuming you have taken undergraduate linear algebra and calculus. I'd start with those two subjects, you really can't build a foundational understanding of modern AI techniques without them.

[mythhouse]

i did linear algebra and calculus using strang and spivak textbooks. Those were classes i enjoy the most. But most of that stuff has atrophied from my brain over the years, do you recommend redoing those courses fast or can i learn when i need it on demand basis.

[viscanti]

You can try a refresher on Jacobians. If you're following everything there well enough, you probably have what you need to move forward (and pick up the rusty parts that you need as you go). If you're completely lost then you probably want to go back for a quick refresher.

[jimbokun]

Review on an on demand basis.

The main concepts are matrix multiplication and derivatives and their significance. Then you can dig into the specifics and review or expand your knowledge as needed.