Question

find the sum of the geomentric series 3+6+12+....+1536​

Answer 1

Answer:

first term a=3

common ratio r =2 (6/3=2. 12/6=2)

last term a*r^(n-1)=1536

3 * 2^n-1 = 1536

2^n-1=512

2^n-1 = 2^9

n-1=9

n=10

now apply the formula and get the answer