Question

Suku ke n dari barisan bilangan 27.9.3.1 ...... adalah. ....​

Answer 1

\begin{lgathered}a = 27 \\ r = \frac{u2}{u1} = \frac{9}{27} = \frac{1}{3}\end{lgathered}a=27r=u1u2​=279​=31​​ 
\begin{lgathered}un = a {r}^{n - 1} \\ un = 27 \times { \frac{1}{3} }^{n - 1} \\ un = {3}^{3} \times {3}^{ - (n - 1)} \\ un = {3}^{3} \times {3}^{ - n + 1} \\ un = {3}^{3 - n + 1} \\ un = {3}^{4 - n}\end{lgathered}un=arn−1un=27×31​n−1un=33×3−(n−1)un=33×3−n+1un=33−n+1un=34−n​