Matematika

Pertanyaan

jika f(x)=√x;x>0 dan g(x)=x/x+1;x bukan samadengan 1 maka tentukan (gof)^-1(2)

2 Jawaban

  • (g o f)(x) = g(f(x))
    = g(√x)
    = (√x) / (√x + 1)

    √x / (√x + 1) = y
    √x = y √x + y
    √x - y√x = y
    √x (1 - y) = y
    √x = y/(1 - y)
    x = [y/(1 - y)]^2
    (g o f)^-1(x) = [x/(1 - x)]^2
    (g o f)^-1(2) = [2/(1 - 2)]^2 = [2/-1]^2 = 4
  • f(x) = √x
    g(x) = x / (x + 1)

    (gof)(x) = g{f(x)}
    (gof)(x) = f(x) / (f(x) + 1)

    y = √x / (√x + 1)
    y (√x + 1) = √x
    y√x + y = √x
    √x - y√x = y
    √x (1 - y) = y
    x = ( y / (1 - y) )²

    (gof)`¹(x) = ( x / (1 - x) )²
    (gof)`¹(2) = ( 2 / (1 - 2) )²
    (gof)`¹(2) = (-2)²
    (got)`¹(2) = 4

    Semoga berguna +_+



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