What is the closed form definition for 4, -12, 36, -108?

Hagen asked Jul 11, 2023

343,843 views

23 votes

Hagen asked Jul 11, 2023

by Hagen

2.4k points

Your comment on this question:

Email me at this address if a comment is added after mine:Email me if a comment is added after mine

Privacy: Your email address will only be used for sending these notifications.

Email me at this address if my answer is selected or commented on:Email me if my answer is selected or commented on

Privacy: Your email address will only be used for sending these notifications.

25 votes

we see that

$\begin{gathered} (-12)/(4)=-3 \\ (36)/(-12)=-3 \\ (-108)/(36)=-3 \end{gathered}$

Then, we have a geometric sequence, and each time we need to muliply by -3 starting from 4, so the closed-form is

so, the answer is the second one.

Maduranga E answered Jul 15, 2023

3.3k points

Email me at this address if a comment is added after mine:Email me if a comment is added after mine

Privacy: Your email address will only be used for sending these notifications.

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

1.6m questions

2.0m answers