Dik deret 2+5+8+... carilah nilai S5=

Barisan dan Deret

U1 atau a = 2

Beda = U2 - U1 = 5 - 2 = 3

Sn = n/2 (2.a + (n-1)).b
S5 = 5/2 (2.2 + (5-1)).3
S5 = 5/2 (4 + 4.3)
S5 = 5/2 × 4 + 12
S5 = 5/2 × 16
S5 = 40

Semoga membantu :)