rumus suku ke-n barisan aritmetika Un=4n+2 maka jumlah 10 suku pertama deret yang bersesuaian ialah?

u2 = 4n+2 = 4(2)+2 = 8+2= 10
u1 = 4(1) + 2 = 4+2 = 6

a= 6
b= u2-u1 = 10-6 = 4

s10 = n/2 (2a +(n-1)b)
= 10/2 (2(6) + (10-1)4)
= 5 ( 12 + 36)
= 5 . 48
= 240

Diketahui
Un = 4n + 2
dit : S10

maka
U1 = a = 4(1) + 2 = 6
U10 = 4(10) + 2 = 42

Sn = (n/2) [a + Un]
S10 = (10/2) [6 + 42]
S10 = 5 [48]
S10 = 240