Tolong dibantu ya…….​

Jawaban:

(n + 1 ) (n+2)/2

Penjelasan dengan langkah-langkah:

(n+1) (n+2) / 2

(1+1) (1+2) / 2 = 2.3/2 = 3

(2+1) (2+2) / 2 = 3.4/2 = 6

(3+1) (3+2) / 2 = 4.5/2 = 10

(4+1) (4+2) / 2 = 5.6/2 = 15