calculer des images
f (x) = - x² + 4 x - 2
f ( 0) = - 2
f (2) = - ( 2 )² + 4 * 2 - 2 = - 4 +8 - 2 = 2
c'est la courbe noire
g (x) = x² + 2 x - 2
g ( 0) = - 2
g ( - 2 ) = 4 - 4 - 2 = - 2 courbe bleue
donc h (x) = courbe rouge
- 3 x² - 2 x + 1 = 0
Δ = ( - 2 )² - 4 ( - 3 * 1 ) = 4 + 12 = 16 = 4 ²
x 1 = ( 2 - 4 ) / - 6 = - 2 / - 6 = 1 /3
x 2 = ( 2 + 4 ) / - 6 = 6 / - 6 = - 1
2 x² - 10 x + 5 = 0
Δ = ( - 10 )² - 4 ( 2 * 5) = 100 - 40 =60 = ( 2 √15 )²
x 1 = ( 10 - 2√15) / 4
x 2 = ( 10 + 2 √15 ) / 4
- x² + 3 x - 4/3 = 0
Δ = ( 3)² - 4 ( - 1 * - 4/3 ) = 9 - 4*4/3 = 9 - 16/3 = ( 27 - 16)/3 = 11/3
x 1 = ( - 3 - √11/3 ) / - 2
x 2 = ( - 3 + √11/3 ) / - 2
- 2 x² + 12 x - 18 = 0
Δ = 12² - 4 ( - 2 *-18) = 144 - 144 = 0
Δ = 0
x0 = - 12 /- 4 = 3
