deret geometri 81+27+9+3+1+... suku ke-7 dari deret tersebut adalah...

a = 81
rasio = 27 / 81 = 1/3
[tex] u_{7} = a r^{n-1} \\ u_{7} = 81 * \frac{1}{3} ^{7-1} \\ u_{7} = 3^{4} * \frac{1}{3} ^{6} \\ u_{7} = 3^{4} * \frac{1}{3^{6}} \\ u_{7} = \frac{1}{3^{2}} \\ u_{7} = \frac{1}{9} [/tex]

a=81
r=27/81=1/3

u7=ar^6
= 81.(1/3)^6
=3^4 / 3^6
= 1/3^2
=1/9