Matematika

Pertanyaan

jika f(x)=x2-5x+2/x-4, nilai f'(x)=

2 Jawaban

  • diangggap gini .... f(x)=(x^2-5x+2)/(x-4)
    u = x² - 5x + 2 ... u' = 2x - 5
    v = x - 4 ............ v' = 1
    f'(x) = (u'v - v'u)/v²
    = ((2x - 5)(x - 4) - 1(x² - 5x + 2))/(x - 4)²
    = (2x² - 13x + 20 - x² + 5x - 2)/(x - 4)²
    = (x² - 8x + 18)/(x - 4)²
  • Rumus:
    Jika f(x) = u(x)/v(x), maka f'(x) = (u'(x).v(x) - u(x).v'(x))/(v(x))²

    Pembahasan:
    Misalkan:
    u(x) = x² - 5x + 2
    u'(x) = 2x - 5
    v(x) = x - 4
    v'(x) = 1

    Maka ↓↓↓
    f'(x) = (u'(x).v(x) - u(x).v'(x))/(v(x))²
    f'(x) = ((2x - 5)(x - 4) - (x² - 5x + 2)(1))/(x - 4)²
    f'(x) = (2x² - 13x + 20 - x² + 5x - 2)/(x² - 8x + 16)
    f'(x) = (x² - 8x + 18)/(x² - 8x + 6)

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