Page 18 - FLIPBOOK MATEMATIKA BARISAN DAN DERET

a) 4, 6, 8, 10, ….

U = 4 = 2 + 2 = (2 x 1) + 2
1
U = 6 = 4 + 2 = (2 x 2) + 2
2
U = 8 = 6 + 2 = (2 x 3) + 2
3
U = 10 = 8 + 2 = (2 x 4) + 2
4
….

U = (2 x n) + 2 = 2n + 2
n

U = 2n + 2
n

b) 1, 9, 25, 49, ….

2
U = 1 = 12 = ((2 x 1) – 1)
1
2
U = 9 = 32 = ((2 x 2) – 1)
2
2
U = 25 = 52 = ((2 x 3) – 1)
3
2
U = 16 = 72 = ((2 x 4) – 1)
4
….

2
U = (2n - 1)
n

Contoh 5

1
Suatu barisan bilangan dengan rumus = ( )

2
a) Tulis empat buah suku pertamanya

b) Berapa suku ke-5 dan ke-7?

Jawab :

1
a) = ( )

2
1
1 1
= ( ) =
1
2
2

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