Matematika

Pertanyaan

fungsi komposisi matematika
f(x)=2-x g(x)=x2-1 h(x)=-2x+2

d tanya
a.(fog) (2)=
b.(goh) (3)=
c.(foh) (1)=
d.(hog) (x)=
e.(hog) (x)=
f.((fog)oh) (x)=
g.(fo(goh)) (x)=
h.((goh)of) (x)=
i.(go(foh)) (x)=
j.(ho(fog)) (x)=

1 Jawaban

  • f(x) = 2 - x
    g(x) = [tex]x^2[/tex] - 1
    h(x) = -2x + 2
    a. (fog)(x) = 2 - ([tex]x^2[/tex] - 1) = 2 - [tex]x^2[/tex] +1 = 3 - [tex]x^2[/tex]
    (fog)(2) = 3 - [tex]2^2[/tex] = 3 - 4 = -1

    b. (goh)(x) = [tex](-2x+2)^2[/tex] - 1 = [tex]4x^2[/tex] - 8x + 4 - 1 = [tex]4x^2[/tex] - 8x + 3
    (goh)(3) = [tex]4(3^2)[/tex] - 8(3) + 3 = 36 - 24 + 3 = 15

    c. (foh)(x) = 2 - (-2x + 2) = 2 + 2x - 2 = 2x
    (foh)(1) = 2 (1) = 2

    f. (fog)(x) = 3 - [tex]x^2[/tex] (lihat soal a)
    ((fog)oh) (x) = 3 - [tex](-2x+2)^2[/tex] = 3 - ([tex]4x^2[/tex] - 8x + 4) = 3 - [tex]4x^2[/tex] + 8x - 4 = [tex]-4x^2[/tex] + 8x - 1

    g. (goh)(x) = [tex]4x^2[/tex] - 8x + 3 (lihat soal b)
    (fo(goh))(x) = 2 - ([tex]4x^2[/tex] - 8x + 3) = 2 - [tex]4x^2[/tex] + 8x - 3 = [tex]-4x^2[/tex] + 8x - 1

    h. (goh)(x) = [tex]4x^2[/tex] - 8x + 3 (lihat soal b)
    ((goh)of)(x) = [tex]4(2-x)^2[/tex] - 8(2 - x) + 3 = 4(4 - 4x + [tex]x^2[/tex]) - 16 + 8x + 3 = 16 - 16x + 4[tex]x^2[/tex] - 16 + 8x + 3 = 4[tex]x^2[/tex] - 8x + 3

    i. (foh)(x) = 2x (lihat soal c)
    (go(foh))(x) = [tex](2x)^2[/tex] - 1 = 4[tex]x^2[/tex] - 1

    j. (fog)(x) = 3 - [tex]x^2[/tex] (lihat soal a)
    (ho(fog))(x) = -2(3 - [tex]x^2[/tex]) + 2 = -6 + 2[tex]x^2[/tex] + 2 = 2[tex]x^2[/tex] - 4

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