Question

if a=1, r=2, find sn for the g.p​

Answer 1

Answer:

The answer is $2^n-1$

Step-by-step explanation:

Concept:

Sum of first $n$ terms of a G.P. with first term $a$ and common ratio $r$ is

                                      $\boxed{\text{S}_n=\dfrac{a(r^n-1)}{r-1}}$

Here given $a=1,r=2$

Therefore

                   $\text{S}_n=\dfrac{1(2^n-1)}{2-1}=2^n-1$