Question

The nth term of a geometric sequence is a sub n =a sub 1 times r ^n-1 , where a sub 1 is the first term and r is the common ratio. Identify a sub 1 and r for each geometric sequence.

Answer 1

Answer/Step-by-step explanation:

Common ratio of a sequence can be gotten by dividing any of the consecutive term in a sequence, by the term before it.

Thus,

For the sequence,
`3, 9, 27. . .` :
`a_1 = 3`

`r = (9)/(3) = 3`

For the sequence,
`8, 4, 2, 1. . .` :
`a_1 = 8`

`r = (4)/(8) = (1)/(2)`

For the sequence,
`-16, 64, -256 . .` :
`a_1 = -16`

`r = (64)/(-16) = -4`