Bonjour
2) f(2) = (4*2+2)/(1+2²) = 10/5 = 2
f(0) = (4*0+2)/1+0²) = 2/1 = 2
donc oui
3) f(1/2) = (4*1/2+2)/(1+(1/2)²) = 4/5/4 = 4*4/5 = 16/5
4) f(x) = 0
4x+2/1+x² = 0
(4x + 2 )/( 1+x² ) *( 1+x² ) = 0*(1+x²)
4x + 2 = 0
4x = -2
x= -2/4 = -1/2
donc l'antécédent de 0 est -1/2
bonne journée
