Réponse :
Explications étape par étape
Bonsoir
Tableau de variation :
f(x) = 10x^2 - 7x + 1/4
f ´(x) = 20x - 7
20x - 7 = 0
20x = 7
x = 7/20 = 0,35
f(0,35) = 10 * 0,35^2 - 7 * 0,35 + 1/4
f(0,35) = 1,225 - 2,45 + 1/4
f(0,35) = -1,225 + 1/4
f(0,35) = -1,225 + 0,25
f(0,35) = -0,975
x...........|-inf...................0,35...................+inf
f ‘(x).....|...........(-).............o.................(+)..............
f(x).......|\\\\\\\\\\\\\\\\(-0,975)///////////////////
\ : décroissante
/ : croissante
g(x) = (7 - x)(7 + x)
g(x) = 49 - x^2
g’(x) = -2x
-2x = 0
x = 0
g(0) = (7 - 0)(7 + 0) = 7 * 7 = 49
x............|-inf...................0......................+inf
g’(x)......|...........(+)..........o.........(-).............
g(x).......|//////////////////49\\\\\\\\\\\\\\\\\\\\
