Matematika

Pertanyaan

Hitunglah nilai komposisi dari :
B. (Gof) = xpangkat2 + x - 12 dan f(x) = x - 3 maka g(x) = ..?
C. F(x) = akar x+1 , g(x) = xpangkat2 - 2 dan h (x) = akar 1 - 2 x carilqh nilai x apabilq (fogoh) (x) = 5?

2 Jawaban

  • B
    .
    (gof) (x)= x²+x-12
    g(x-3)= x²+x-12
    g(x)=(x+3)²+(x+3)-12
    = x²+6x+9+x-9
    =x²+7x

    C.
    f(x)= √(x+1)
    g(x)= x²-2
    h(x)= √(1-2x)

    (fogoh)(x) =5

    (fog)oh) (x)
    (fog) (x) = √(g(x) + 1)
    =√(x²-2+1)
    =√(x²-1)

    maka
    (fog)oh) (x)
    √(h(x) ²-1)
    √(√(1-2x)²-1)
    √(1-2x)-1)
    =√-2x

    (fogoh) (x) = 5
    √(-2x) =5
    -2x=5^½
    x= -5^½ / 2
  • Langsung aja y

    Bagian B
    (gof)(x) = g{f(x)}
    x² + x - 12 = g(x - 3)

    misal :
    x - 3 = a
    x = a+3

    soal menjadi →
    g(a) = (a+3)² + (a+3) - 12
    g(a) = a² + 6a + 9 + a + 3 - 12
    g(a) = a² + 7a

    g(x) = x² + 7x

    Bagian C

    misal
    (fog)(x) = s(x)

    = f{g(x)}
    = √g(x) + 1
    = √x² - 2 + 1
    = √x²-1

    (soh)(x) = s{h(x)}

    = √h(x) - 1
    = √1-2x - 1
    = √-2x

    (fogoh)(x) = √-2x
    5 = √-2x
    5² = -2x
    -2x = 25
    x = 25 : -2
    x = -12,5

    Semoga berguna +_+

Pertanyaan Lainnya