Matematika

Pertanyaan

Quiz Math ^_^

Hitunglah
[tex] \dfrac{1}{8} + \dfrac{1}{24} + \dfrac{1}{48} + \cdots + \dfrac{1}{10200} [/tex]

Petunjuk:
1. Cari pola penyebut
2. Gunakan prinsip deret teleskopik

1 Jawaban

  • jawab

    1/8  = 1/(4.1.2)
    1/24 = 1/(4.2.3)
    1/48= 1/(4.3.4)
    ...
    1/10.200 = 1/(4)(50)(51)

    50
    ∑  1/(4n(n+1)) 
    i = 1

    1/4 ( 1/(1.2) + 1/(2.3) + ...+1/(50.51))=
    = 1/4(1- 1/2 + 1/2 -1/3 + 1/3 - 1/4 + ...+1/50 -1/51)
    = 1/4 (1 - 1/51)
    = 1/4 (50/51)
    = 25/102 

Pertanyaan Lainnya