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1 vote
Find the 9th term of the geometric sequence

9
,

18
,
36
,
.
.
.
9,−18,36,...

1 Answer

6 votes

Answer: This is a geometric sequence, because each term is obtained by multiplying the previous term by a constant ratio. In this case, the ratio is -2.

To find the 9th term, we can use the formula for the nth term of a geometric sequence:

a_n = a_1 * r^(n-1)

where:

a_n is the nth term of the sequence

a_1 is the first term of the sequence (9)

r is the common ratio (-2)

n is the term number (9)

Plugging in the values:

a_9 = 9 * (-2)^(9-1) = 9 * (-2)^8 = 9 * -256 = -2304

So the 9th term of the sequence is -2304

User Mark Kromer MSFT
by
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