Question

which spreadsheet would be used to compute the first 7 terms of the geometric sequence an=20*(1/2)^n-1

Answer 1

The appropriate spreadsheet is the one that makes use of the proper formula and appropriate cell references.

Answer 2

Option 4

Explanation:

Given : Geometric sequence
`a_n=20* ((1)/(2))^(n-1)`

To find : Which spreadsheet would be used to compute the first 7 terms of the geometric sequence ?

Solution :

Geometric sequence is in the form
`a+ar+ar^2+ar^3+...`

Where, a is the first term and r is the common ratio.

The sum of sequence is represented as
`S_n=\sum^(7)_(n=0) ar^n`

or
`S_n=\sum^(7)_(n=1) ar^(n-1)`

According to question,

a=20 and
`r=(1)/(2)`

Sum of first terms is,

`S_1=20((1)/(2))^(n_1-1)` ,
`n_1=1`

Sum of second terms is,

`S_2=20((1)/(2))^(n_2-1)` ,
`n_2=2`

Sum of third terms is,

`S_3=20((1)/(2))^(n_3-1)` ,
`n_3=3`

Sum of four terms is,

`S_4=20((1)/(2))^(n_4-1)` ,
`n_4=4`

Sum of five terms is,

`S_5=20((1)/(2))^(n_5-1)` ,
`n_5=5`

Sum of six terms is,

`S_6=20((1)/(2))^(n_6-1)` ,
`n_6=6`

Sum of seven terms is,

`S_7=20((1)/(2))^(n_7-1)` ,
`n_7=7`

Therefore, Option 4 is correct.

The spreadsheet 4 would be used to compute the first 7 terms of the geometric sequence.