Exercice

Calculer   A = 2 + 3 2 3 + 2 3 2 + 3 .

A= 2+ 3 2 3 + 2 3 2+ 3 = 2+ 3 2 3 + 2 3 2+ 3  car 2+ 3 0 et 2- 3 0 = 2+ 3 2 3 2 3 + 2 3 2+ 3 2+ 3 = (2+ 3 )(2 3 ) 2 3 + (2 3 )(2+ 3 ) 2+ 3 = 43 2 3 + 43 2+ 3 = 1 2 3 + 1 2+ 3 = 2+ 3 +2 3 (2 3 )(2+ 3 ) = 4 43 =4 Donc  A = 4