Question

find the sum of the series ​

Answer 1

Step-by-step explanation:

Given series is 1+2+4+ ____upto 9 terms

Here a=1,r=12=24=2

and n=9

We know, Sn=a[r−1rn−1],r>1

=1[2−129−1]

=1256−1=255

Therefore, the sum of the series is 255.