Matematika

Pertanyaan

grafik fungsi kuadrat yg mempunyai titik puncak (2,-3) serta melalui titik (1,-2) mempunyai persamaan...
Tolong di bantu ya kaka :)

2 Jawaban

  • GRAFIK FUNGSI KUADRAT

    (xp , yp) = (2 , -3)
    (x , y) = (1 , -2)

    PK umum
    ax² + bx + c = y

    xp = -b/2a
    2 = -b/2a
    -b = 4a
    b = -4a

    Pknya
    y = ax² - 4ax + c

    Titik puncak (2 , -3)
    -3 = a(2)² - 4a(2) + c
    4a - 8a + c = -3

    -4a + c = -3


    Titik (1 , -2)
    -2 = a(1)² - 4a(1) + c
    a - 4a + c = -2
    -3a + c = -2


    -4a + c = -3
    -3a + c = -2
    ------------------- -
    -a = -1
    a = 1

    -3a + c = -2
    -3 + c = -2
    c = 1

    b = -4a
    b = -4

    PK
    y = x² - 4x + 1

  • [tex]y = a(x - xp) {}^{2} + yp \\ y= a(x - 2) {}^{2} - 3melalui \: (1. - 2) \\ - 2 = a(1 - 2 ) {}^{2} - 3 \\ - 2 = a - 3 \\ a = 1 \\ y =1(x - 2) {}^{2} - 3 \\ y = {x}^{2} - 4x + 4 - 3 \\ y = {x}^{2} - 4x + 1[/tex]
    semoga membantu

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