Hvad er vertexet for y = -x ^ 2 + 2x +4?

Svar:

#(1,5)#

Forklaring:

# "for en parabola i standardformular" y = ax ^ 2 + bx + c #

# "x-koordinatet af vertex er" x_ (farve (rødt) "vertex") = - b / (2a) #

# y = -x ^ 2 + 2x + 4 "er i standardformular" #

# "med" a = -1, b = 2, c = 4 #

#rArrx_ (farve (rød) "toppunkt") = - 2 / (- 2) = 1 #

# "erstatte ligningen for y-koordinat" #

#rArry_ (farve (rød) "toppunkt") = - 1 + 2 + 4 = 5 #

#rArrcolor (magenta) "vertex" = (1,5) #

graf {-x ^ 2 + 2x + 4 -10, 10, -5, 5}