Page 54 - DIGITAL BOOK MUHAMMAD AZWARDI NASUTION

CONTOH 6:

c)Hitunglah jumlah 8 suku yang pertama deret geometri

2 2
6 + 2 + + + .... 6  1− ( ) 
8
1
3 9 S = 3
8
1− 1
3
JAWAB:  1 

a = U = 6 S = 6 1− 3 8 



1

U 2 1 8 2
r = 2 = = 3

U 1 6 3 = . 6 3  1  − 1 

2  3 8 

a( − n )  1 
1 r
S = ,r  1 = 9 1− 8 

n
−
1 r  3 

= 9 6561− 1 = 6560 = 8 728

 6561  729 729