Matematika

Pertanyaan

tentukan selisih nilai maksimal dan minimum dari fungsu f(x) satu pertiga X pangkat 3 + setengah X kuadrat - 2X + 5

1 Jawaban

  • f(x) = ⅓x³ + ½x² - 2x + 5
    f'(x) = x² + x - 2

    Nilai min dan max ddpt saat f'(x) = 0

    x² + x -2 = 0
    (x + 2)(x - 1) = 0
    x = -2 v x = 1

    Masukkan

    f(-2)
    = 1/3 (-2)³ + 1/2 (-2)² - 2(-2) + 5
    = 1/3 (-8) + 1/2 (4) + 4 + 5
    = -8/3 + 2 + 4 + 5
    = 11 - 8/3
    = 25/3

    f(1)
    = 1/3 (1)³ + 1/2 (1)² - 2(1) + 5
    = 1/3 + 1/2 - 2 + 5
    = 1/3 + 1/2 + 3
    = 2/6 + 3/6 + 18/6
    = 23/6

    25/3 - 23/6
    = 50/6 - 23/6
    = 27/6

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