Question

Find the 9th terms of the G.P. with first term 4 and common ratio 2.

Answer 1

Clearly, the given GP has first term $a=4$ and common ratio $r=2$.

$n^{th}term{a}_n=a{r}^n$

$\therefore a_4=a{r}^3\Rightarrow a_4=4\times (2{)}^3=32$

and $a_9=a{r}^8\Rightarrow a_9=4\times (2{)}^8=1024$