Analysis: p_sheet #4 study of polynomial functions

[madvid]

Create a practise sheet on the polynomial functions:

• [x] discriminant and solutions to P(x) = 0
• [x] variation of polynomial functions
• [x] factorized form of a polynomial function + graphical interpretation
• [ ] first step to taylor serie
• [ ] study of a overfitting cas with use of biais and variance and cost of models in function of polynom degree.