9514 1404 393
Answer:
see attached
Step-by-step explanation:
a) The first 5 partial sums are listed in the table in the attachment.
__
b) Sigma notation makes use of the general term shown:
__
c) The sum appears to be close to 3/4. (For large n, a calculator cannot evaluate the terms of the series--they are too small.) The attachment shows the 100th sum to be rounded to 3/4 (from 12 significant digits).
Answer:
700 lei
Step-by-step explanation:
You have a geometric sequence for which you know the common ratio and the last term.
There are only three terms, so you can solve the problem in either of two ways.
1. The brute force method (easiest for only a few terms)
Each term is half the one before it, so each term is double the one after it.
3rd term = 100 lei
2nd term = 200
1st term = 400
Total = 700 lei
Oana spent 700 lei
2. Using formulas (best for longer sequences)
The general formula for your sequence is
aₙ = a₁rⁿ⁻¹
For your sequence,
a₃ = 100; r = 0.5
(a) Calculate a₁
Set the last term equal to the general formula.
a₃ = a₁(0.5)ⁿ⁻¹
100 = a₁(0.5)² = 0.25a₁
a₁ = 100/0.25 = 400
(b) Calculate the sum
The general formula for the sum of a geometric sequence is
Oana spent 700 lei.
Hello!
Explanation:
First, you had to do is multiply by the numbers. And don't forget to used variables.
Answer: →
Hope this helps!
Thanks!
-Charlie