Find the sum of the indicated terms of the geometric sequence
n=4
E 8(4)^n-1
n=1
a. s= 688
b. s= 696
c. s= 2720
d. s= 680
e. s= 672
The sum,S, is given by :
S = a1 [ 1 - r^n] / [ 1 - r ] where a1 = 8, r = 4 and n = 4 .... so we have
S = 8 [ 1 - 4^4] / [1 - 4] = 680
