soal geometri dengan caranya tentukan= 1. 2+5+8.......+107 2. 1+5+9.......401
Matematika
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Pertanyaan
soal geometri dengan caranya
tentukan=
1. 2+5+8.......+107
2. 1+5+9.......401
tentukan=
1. 2+5+8.......+107
2. 1+5+9.......401
1 Jawaban
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1. Jawaban Anonyme
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