diketahui deret aritmatika 2+4+6+8+....+60 hasil deret di atas?

Deret Aritmatika
a = 2
b = (U2 -U1)
= 4 - 2 = 2

Un = 60
a + (n-1)b = 60
2 + (n-1)2 = 60
2(n-1) = 60 - 2
2(n - 1) = 58
(n - 1) = 58/2
n - 1 = 29
n = 29 + 1 = 30

Sn = n/2 × (a + Un)
= 30/2 × (2 + 60)
= 15 × 62
= 930

Semoga membantu ^^

Mapel : Matematika

Kelas : 8, 9

Bab : Barisan dan Deret Bilangan
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→ Nilai a = 2

→ Nilai b = 4 - 2 = 2

→ Un = 60


Ditanya → Jumlah n suku pertama


Jawaban :
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Un = 60

a + (n - 1)b = 60

2 + 2n - 2 = 60

2n = 60

n = 60/2

n = 30 ✔


Maka, Jumlah 30 suku pertama nya

Sn = n/2 [a + Un]

S30 = 30/2 [2 + 60]

S30 = 15 x 62

S30 = 930 ✔