Current TODO

1. Finish Multivariate gaussian till the Moments parts,
2. solve some problems on chapter 2

Important stuff I learned that may help

1. Fubini Theorem: Multiplcation of two integrals is an iterative integrals. What is an iterative integral
2. Revision on Lagrangian multipliers

Current understanding of multinomial:

Generalized binomial, it is literally a binomial

TODO: revise combinations and permutations