# Add linear pdf using RooPolynomial

Define a linear PDF using a `RooPolynominal`

of order 1. The current implementation takes one parameter `a1`

and defines a pdf based on the polynomial `1 + a1 x`

.

It might be more elegant to implement a general class for any order polynomial but that would require optional parameters and I don't know if the framework can deal with that. So for now I've implemented a linear pdf with a fixed number of parameters, which is enough for my use case.