Question

What is the value of r of the geometric series?

Sigma-Summation Underscript n = 1 Overscript 3 EndScripts 1.3 (0.8) Superscript n minus 1

0.8

1.3

3.0

3.2

Answer 1

A

Explanation:

Just took test

Answer 2

0.8

Explanation:

Given the formula for the geometric series expressed as;

`\sum \left \{ {3} \atop {1}} \right 1.3(0.8)^(n-1)`

The nth term of a geometric progression is expressed as;

`T_n = ar^(n-1)\\`

a is the first term

r is the common ratio

Comparing both equations;

`0.8^(n-1) = r^(n-1)\\Cancel \ the \ powers\\0.8 = r\\r = 0.8\\`

Hence the value of r of the geometric series is 0.8