Mohon bantuan nya, beserta cara jalannya yaaa. hitunglah jumlah setiap Deret Aritmatika dibawah ini !! 1. -8+(-4)+0+.... sampai 20 suku 2. ⅓+½+⅔+..... sampai 21 suku 3. 0+x+2x+..... sampai 11 suku
Ghinashoda
A) -8 + (-4) + 0 + ...+ U20 a = -8 dan b = 4 Sn = n/2(2a+(n-1)b) S20 = 20/2( -16 + 19(4)) = 10(60) = 600 b) 2/6 + 3/6 + 4/6 + ...+U21 a = 2/6 dan b = 1/6 S21 = 21/2 (4/6 + 20(1/6)) = 21/2(24/6) = 21(4)/2 = 42 c) 0 + x + 2x + ...+ U11 a = 0 dan b = x S11 = 11/2(0 +10x) = 55x
a = -8 dan b = 4
Sn = n/2(2a+(n-1)b)
S20 = 20/2( -16 + 19(4))
= 10(60)
= 600
b) 2/6 + 3/6 + 4/6 + ...+U21
a = 2/6 dan b = 1/6
S21 = 21/2 (4/6 + 20(1/6))
= 21/2(24/6)
= 21(4)/2
= 42
c) 0 + x + 2x + ...+ U11
a = 0 dan b = x
S11 = 11/2(0 +10x)
= 55x