Matematika

Pertanyaan

soal geometri dengan caranya
tentukan=
1. 2+5+8.......+107
2. 1+5+9.......401

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  • Barisan Aritmatika

    2 + 5 + 8 + ... + 107
    n = (107 - 2)/(5 - 2) + 1
    n = 36

    2 + 5 + 8 + .. + 107 = S36

    Sn = (n/2)(a + Un)
    S36 = (36/2)(2 + 107)
    S36 = 18 × 109
    S36 = 1962


    1 + 5 + 9 + ... + 401
    n = (401 - 1)/(5 - 1) + 1
    n = 101

    S101 = (101/2)(1 + 401)
    S101 = 20301

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