Question

What are the values of a1 and r of the geometric series?

2 – 2 + 2 – 2 + 2
a1 = 2 and r = –2
a1 = –2 and r = 2
a1 = –1 and r = 2
a1 = 2 and r = –1

Answer 1

a1 = 2 and r = –1

Explanation:

The answer above is correct.

Answer 2

a1=2 and r=-1

Explanation:

"A geometric series is a series with a constant ratio between successive terms".

Here, we can observe that the first term 'a' is '2'.

And the common ratio 'r' =

Therefore, the first term 'a' is 2 and common ratio 'r' is '-1'.

First term, a, is 2. Next term, -2, is the product of 2 and -1 and is -2. Next term, 2, is the product of -2 and -1. Thus, the first term, a, is 2 and the common ratio, r, is -1