- Calculus covering Derivation, Integration, Multi-Variate
- Linear Algebra
- Differential Equations (May not be relevant here)
'Discrete math' is also useful.
Some of the derivations in the book you can take on faith and not fully prove out to save time, but you should feel 100% comfortable/confident with the notation used.
Let me know what's confusing you and we can try to figure out what you are missing.