Matematika

Pertanyaan

hitunglah 1 + 2 + 3 + 4 + ... + 49 =

2 Jawaban

  • Diketahui:
    a = 1
    b = 2 - 1 = 1

    Pembahasan:
    Un = a + (n - 1)b
    49 = 1 + (n - 1)1
    49 = 1 + n - 1
    n = 49

    Maka,
    Sn = n/2(2a + (n-1)b)
    S49 = 49/2(2.1 + (49-1)1)
    S49 = 49/2(2 + 48)
    S49 = 49/2(50)
    S49 = 49(25)
    S49 = 1225
  • n = 49
    a = 1
    Un = 49

    Sn = n/2 × (a + Un)
    S49 = 49/2 × (1 + 49)
    S49 = 49/2 × 50
    S49 = 1225

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