Math CentralQuandaries & Queries


Subject: nth term
Name: Sarah
Who are you: Student

I am having difficulty in finding the nth term for 7,49,343,2401. Could you please help me in finding the correct answer?

Hi Sarah. Here's a hint: it is a "geometric sequence". So that means that each successive term is multiplied by the same factor. For example, 9, 27, 81, 243, ... has a common factor of 3 (each term is just the last term times 3). Yours is like this. Geometric sequences have an nth term of the form a x fn-1 where a is the first term, f is the common factor and n is the number of the term (nth term).

With my example, the nth term is 9 x 3n-1, which reduces to 3n+1. Can you do something like this for your sequence?

Stephen La Rocque.>

About Math Central


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.
Quandaries & Queries page Home page University of Regina PIMS