Question

Find the sum of the first 8 terms of the following sequence. Round to the nearest

hundredth if necessary.
32,
-16,
8, ...

Answer 1

63.75

Explanation:

this is a geometric progression with a common ratio of -1/2

the formula for the sum of first n numbers is

Sn = (a1(1-r^n)) / 1 - r

so S8 = (32*(1 - 1/2^8)) / (1 - 1/2)

32*(255/256) / 0.5

Sn= 255 / 4 = 63.75