Matematika

Pertanyaan

Deret geometri dengan u5 =16, u6 =8.nilai u1 +u2 +u3 +u4 =...

2 Jawaban

  • U5 = 16
    ar^4 = 16

    U6 = 8
    ar^5 = 8

    ar^5 / ar^4 = 8 / 16
    r = 1/2

    ar^4 = 16
    a(1/2)^4 = 16
    a(1/16) = 16
    a = 256

    S4 = a(1 - r^n) / 1 - r
    S4 = 256 (1 - (1/2)^4) / 1 - 1/2
    S4 = 256 - 16 / 1/2
    S4 = 240 (2)
    S4 = 480
  • r = 8/16
    = 1/2
    U5 = ar^4 = 16
    a = 16×16
    = 256
    S4 = (256×(1 - (1/2)^4) : ( 1 - 1/2)
    = 240 : 1/2
    = 480

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