soal mtk kelas 12 ipa

Jumlah n suku pertama suatu deret geometri dirumuskan dengan Sn=23n-1. Rasio deret tersebut adalah….
A. 8
B. 7
C. 4
D. -1/8
E. -8

Default Asked on January 6, 2016 in Matematika.
Add Comment
2 Answer(s)

Maksudmu 2^3n-1 mungkin

S1=U1= 2^3.1-1= 2^2 = 4
S2= 2^3.2-1 = 2^5 = 32
U2= 32-4 = 28

rasio = U2/U1 = 28/4 = 7 (B)

Train Answered on January 9, 2016.
Add Comment

Sn = 23n – 1

U1 = S1 = 23 (1) – 1 = 22
S2 = 23(2)-1 = 45
S2 = U1 + U2
45 = 22 + U2
U2 = 45 – 22
U2 = 23

r = U2/U1 = 23/22

tapi masih ragu kak.. itu bener 23n – 1 atau 23n– 1
kalau ada fotonya di attach aja kak

Train Answered on January 6, 2016.
Add Comment

Your Answer

By posting your answer, you agree to the privacy policy and terms of service.