Question

Tentukan suku pertama,beda dan rumus ke n ,suku ke 10 serta jumlah 10 suku pertamanya dari 4,7,10,13,.....

Answer 1

Verified answer

A = 4 --> suku pertama
b= 7-4 = 3

u10 = a +9b
      = 4 + 27
       = 31 --> suku ke -10

Sn = n/2 ( a + un)

S10 = 10/2 ( a + u10)
S10    = 10/2 ( 4 + 31)
          = 5 (35)
          = 175 ----> jumlah 10 suku

Answer 2

Verified answer

Suku pertama (a) = 4
Beda (b) = 7 - 4 = 3

Un = a + (n-1)b
U10 = 4 + (10-1).3
U10 = 4 + 9.3
U10 = 4 + 27
U10 = 31

S10 = 10/2 {2(4) + (10-1).3}
S10 = 5 (8 + 9.3)
S10 = 5 (8 + 27)
S10 = 5 (35)
S10 = 175