Question

Diketahui barisan bilangan 2,5,9,14,20,...,... . Tentukan suku ke 30 nya

Answer 1

A = 2 , 5 , 9 , 14 , 20
b = (+3)(+4)(+5)(+6)
c = (+1) (+1) (+1)

U30 = a + (n-1) b + (n-1) (n-2) c/2
= 2 + (30-1) 3 + (30-1) (30-2) 1/2
= 2 + 29 x 3 + 29 x 28 / 2
= 2 + 87 + 406
= 495

semoga membantu:)