A Court of Silver Flames (A Court of Thorns and Roses, 5) (A Court of Thorns and Roses, 4)

A Court of Silver Flames (A Court of Thorns and Roses, 5) (A Court of Thorns and Roses, 4)

Matematika Hitunglah jumlah 20 suku pertama dari barisan 8,1,-6-13,-20

Hitunglah jumlah 20 suku pertama dari barisan 8,1,-6-13,-20

Jawab:

-1170

Penjelasan dengan langkah-langkah:

Sn = (n/2)(2a + (n - 1)b)

S20 = (20/2)((2 x 8) + (20 - 1)(-7))

S20 = 10 (16 + (-133))

S20 = 10(-117)

S20 = -1170