barisan aritmatika : 4,10,16,22 Tentukan : a) nilai a & b b) U10? c) S10? d) S50? e) S100?

Dik. barisan deret aritmatika :
4,10,16,22, ... , Un
Dit. a) a & b
b) U10
c) S10
d) S50
e) S100

Jawab...

a = 4
beda (b) = u2-u1 = 10-4 = 6

#B
U10 = a + 9b
U10 = 4 + 9(6)
U10 = 4 + 54
U10 = 58

#C
Sn = n/2 (2a + (n-1) b)
S10 = 10/2 (2(4) + (9)(6))
S10 = 5 (8+54)
S10 = 5 (62)
S10 = 310

#D
Sn = n/2 (2a + (n-1) b)
S50 = 50/2 (2(4) + (49)(6))
S50 = 25 (8 + 294)
S50 = 25 (302)
S50 = 7550

#E
Sn = n/2 (2a + (n-1)b)
S100 = 100/2 (2(4) + (99)(6))
S100 = 50 (8+594)
S100 = 50 (602)
S100 = 30100

Semoga membantu.. ^__^