Question

Find the value of $n$ if $n$th term of $1,2,4,8,....$ is $1024$.

Answer 1

Given $1,2,4,8,...$

In a G.P.

$a_n=a{r}^{n-1}$

$\Rightarrow 1024=1\times 2^{n-1}$

$\Rightarrow 2^{10}=2^{n-1}$

$\therefore n-1=10$

Hence, $n=11$