TS un petit truc sur le log ...

http://ed.ted.com/lessons/steve-kelly-logarithms-explained

Logarithms, explained - Steve Kelly

What are logarithms and why are they useful? Get the basics on these critical mathematical functions -- and discover why smart use of logarithms can determine whether your eyes turn red at the swimming pool this summer. Lesson by Steve Kelly, animation by TED-Ed.

http://ed.ted.com