Question

Represente gráficamente a função polinomial do 2º grau dada por :

A) Y=x²-4x+3 B) Y=-x²+2x-1

Answer 1

a)
y=x²-4x+3

Xv=-b/2a=4/2=2

Yv=-Δ/4a=-(16-12)/4=-4/4=-1

x=4⇒y=3  (4,3)
x=3⇒y=0   (3,0)
x=2⇒y=-1 V(2,-1)
x=1⇒y=0  (1,0)
x=0⇒y=3  (0,3)

b)
y=-x²+2x+1

Xv=-b/2a=-2/-2=1
Yv=-Δ/4a=-(4+4)/-4=-8/-4=2

x=3⇒y=-2  (3,-2)
x=2⇒y=1    (2,1)
x=1⇒y=2  V(1,2)
x=0⇒y=1    (0,1)
x=-1⇒y=-2  (-1,-2)