Question

take a given sequence of number (Say a, a2, a3​

Answer 1

Step-by-step explanation:

Sequence taken as

a, a2, a3...

Now the common ratio

r=a2/a = a3/a2 = a

Sum

$sum = \frac{a( {r}^{n} - 1)}{r - 1} \\ = \frac{a( {a}^{n} - 1) }{a - 1}$