79.7k views
4 votes
Write the nth rule for each geometric sequence.4) -3, 1, -1/3, 1/9...

User Alex Panov
by
8.2k points

1 Answer

5 votes

In a geometric sequence each term is found by multiplying the previous term by a constant.

To find the nth term in a geometric sequence we use:


a_n=ar^(n-1)

where a is the first term and r is the common ratio.

To find the common ratio we can divide the second term by the first:


(1)/(-3)=-(1)/(3)

and the third one by the second:


(-(1)/(3))/(1)=-(1)/(3)

we notice that this in fact is the common ratio. Now we plug it in the formula above, therefore the geometric sequence is:


a_n=-3(-(1)/(3))^(n-1)

User Thinkhy
by
8.5k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories