Réponses

2014-09-12T22:21:10+02:00
^2 indique au carré
(a+b+c)^2=((a+b)+c)^2=(a+b)^2+c^2+2c(a+b)
=a^2+b^2+2ab+c^2+2ac+2bc
=a^2+b^2+c^2+2ab+2ac+2bc