Réponse :
bonjour
f (0) = 0 et f ( 2) = 3
( 3 - 0 ) / ( 2 - 0 ) = 3/2
ax = 3 x /2
f (2) = 3
2 * 3 /2 + b = 3
6/2 + b = 3
b = 3 - 3 = 0
f (x) = 3 x /2 + 0
f ( 0 ) = 4 et f ( 4 ) = 0
( 0 - 4 ) / ( 4 - 0 ) = - 4 /4 = - 1
ax = - x
f ( 0 ) = 4
0 + b = 4 donc b = 4
f (x) = - x + 4
d'où f ( 4 ) = - 4 + 4 = 0
continue
