Jawabanmu

2014-05-23T16:19:51+07:00
S = a / 1-r
8 = 4 / 1-r
8 (1 - r) = 4
8 - 8r = 4
-8r = -4
r = 1/2

2014-05-23T16:23:54+07:00
Deret tak hingga =  \frac{a}{1-r}
8  =  \frac{4}{1-r}
8. (1-r) = 4
8 - 8r = 4
8 - 4 = 8r
4 = 8r
r = \frac{4}{8}
r =  \frac{1}{2}