Question

Dik.barisan bilangan
3,4,7,12,19 rumus suku ke n
Tolong dijawab yahh

Answer 1

Penyelesaian :

BARISAN BILANGAN

3, 4, 7, 12, 19, ... → a = 3

1, 3, 5, 7, .... → b = 2

2, 2, .... → c = 2

Un = a + (n - 1) . b + 1/2 . (n - 1) . (n - 2) . c

Un = 3 + (n - 1) . 2 + 1/2 . (n - 1)- (n - 2) . 2

Un = 3 + n - 1 + n² - 2n - n + 2

Un = n² - 2n + 4