Use the partial sum formula to find the partial sum of the given geometric sequence.
-Find the sum of the first five terms of the geometric sequence 4, -8, 16, . . .
A) -124
B) -44
C) 44
D) 124

Question

Quizplus · Accepted Answer

The first term (a) is 4, the common ratio (r) is -2, and the number of terms (n) is 5. The partial sum formula for a geometric sequence is S_n = a(1-r^n)/(1-r). Plugging in the values: S_5 = 4(1-(-2)^5)/(1-(-2)) = 4(1+32)/3 = 4(33)/3 = 44.

Use the Partial Sum Formula to Find the Partial Sum