Question

The first 3 terms in a geometric sequence are 1.1, 1.65, and 2.475.

Part A: What is the sum of the first 6 terms of the sequence? Show your work.

Part B: How does the sum of the series differ from the 6th term? Explain.

Part C: If the nth term in this sequence represents the total amount of protein a cell has produced in n hours, what would you use to find the amount of protein produced by 4 hours: the 4th term of the sequence, or the sum of the first 4 terms? Explain how you know.

Answer 1

r=1.65/1.1=1.5=22.8594

I have the same question on my exam too!!!

Answer 2

s = a(1-r^6)/(1-r)
= 1.1(1-1.5^6)/(1-1.5)
= 22.8594
correct

s-T6 = 22.8594 - 1.1*1.5^5 = 14.5063
Ummm. the 6th term is the 6th term.
The sum is gotten by adding up all 6 terms.

Use the nth term. It represents the amount produced in n hours. The sum here might represent the total amount in n cells, where each cell is started in successive hours.