Réponses

2014-04-25T16:55:27+02:00
Bonjour

A = √5 + 3
A² = (√5 +3)² = 5 + 6√5 + 9 = 14 + 6√5

B = √5 - 3
B² = 5 - 6√5 +9  = 4 √5
AB
(√5 +3) ( √5 -3)
= 5 - 3√5 + 3√5 -9
= -4

(A +B)² = (√5+3 +√5 -3)² = (√5)² = 5