Matematika

Pertanyaan

Bagaimana cara menyederhanakan pecahan rasional tidak sejati.? Misal :
x^5 + x^4 -x -1
___________
x^3 -1

2 Jawaban

  • x^5 + x^4 - x - 1
    1 | 1 ... 1 ... 0 .. 0 .. -1 ... -1
    .. | ..... 1 ... 2 ... 2 .. 2 .. 1
    --------------------------------+
    ... 1 ... 2 ... 2 ... 2 .. 1 .. | 0
    (x^4 + 2x^3 + 2x^2 + 2x + 1) (x - 1)

    x^3 - 1
    1 | 1 ... 0 ... 0 ... -1
    .. | ..... 1 ..... 1 ... 1
    ---------------------- +
    .... 1 ... 1 ... 1 ..| 0
    (x^2 + x + 1) (x - 1)

    Jadi bentuk sederhana dari
    (x^5 + x^4 - x - 1)/(x^3 - 1)
    = (x^4 + 2x^3 + 2x^2 + 2x + 1)(x - 1) /(x^2 + x + 1)(x - 1)
    = (x^4 + 2x^3 + 2x^2 + 2x + 1)/(x^2 + x + 1)
  • Jawab:

    x^5 + x^4 -x -1
    ____________
    x^3 - 1


    x^4(x+1) - (x+1)
    ____________
    x^3 - 1


    (x+1) (x^4 - 1)
    __________
    x^3 - 1


    (x+1) ((x^2)^2 - 1^2)
    ________________
    x^3 - 1


    (x+1) (x^2 + 1) (x^2 - 1)
    __________________
    x^3 - 1


    (x+1) (x^2 + 1) (x^2 - 1^2)
    ____________________
    x^3 - 1


    (x+1) (x^2 + 1) (x+1) (x-1)
    ___________________
    x^3 - 1


    (x+1)^2 (x^2 + 1) (x-1)
    _________________
    x^3 - 1


    (x+1)^2 (x^2 + 1) (x-1)
    _________________
    x^3 - 1^3

    (x+1)^2 (x^2 + 1) (x-1)
    _________________
    (x-1)(x^2 +(x)(1) + 1^2)


    (x+1)^2 (x^2 + 1) (x-1)
    _________________
    (x-1)(x^2 +x .1 + 1


    (x+1)^2 (x^2 + 1) (x-1)
    _________________
    (x-1)(x^2 + x + 1
    Karena (x-1) sudah sama atas dan bawah => boleh dicoret aja.
    Maka hasilnya =

    (x+1)^2 (x^2 + 1)
    _________________
    x^2 + x + 1


    *TERIMA KASIH*


















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