hitunglah jumlah 13 suku pertama bilangan ganjil

1,3,5,7,9,11,13,15,17,19

1 + 3 + 5 + 7 + 9 + 11 + ... + n

Dik . a = 1 , b=2 , n = 13
[tex]sn = \frac{n}{2} (2a + (n - 1)b) \\ s13 = \frac{13}{2} (2(1) + (13 - 1)2 \\ s13 = 182[/tex]