use formula Sn to find the sum of the first five terms of ea

use formula Sn to find the sum of the first five terms of each geometric sequnce 2, 8, 32, 128, ...

the answer is 682.

Solution

Sum of Geometric series:

wher r is the common difference.In our case r= 8/2 = 32/8 = 4

we are given first four terms , so fifth term = 128*4 = 512

Sum of first five terms =2+ 8+ 32+ 128+ 512 = 682