Tentukan n jika 3+9+27+...+n=363

a = 3
r = 9/3 = 3
Sn = 363

Sn = 363
{a× [(r^n)-1]}/(r-1) = 363
{3 × [(3^n) - 1]} / (3-1) = 363
{3 × [(3^n) - 1]} / (2) = 363
{3 × [(3^n) - 1]} = 363 × 2
{3 × [(3^n) - 1]} = 726
[(3^n) - 1] = 726/3
[(3^n) - 1] = 242
(3^n) = 242 + 1
(3^n) = 243
(3^n) = 3^5
n = 5

[tex]sn = \frac{a( {r}^{n} - 1) }{ r - 1} \\ 363 = \frac{3( {3}^{n} - 1 }{3 - 1} \\ 363 = \frac{3( {3}^{n } - 1) }{2} \\ \frac{363 \times 2}{3} = {3}^{n} - 1 \\ 242 = {3}^{n} - 1 \\ 242 + 1 = {3}^{n } \\ 243 = {3}^{n} \\ {3}^{5} = {3}^{n} \\ n = 5[/tex]