Question

The first four terms of a sequence are shown below. 18,25,32,39.... Which expression can be used to find the nth term of the sequence?

Answer 1

Given:

First four terms of a sequence are 18,25,32,39....

To find:

The expression for the nth term of the sequence.

Solution:

It is clear that, 18,25,32,39 are in AP.

Here,

First term: a=18

Common difference: d = 25-18 = 7

The nth term of an AP is

$a_n=a+(n-1)d$

On substituting the values, we get

$a_n=18+(n-1)7$

$a_n=18+7n-7$

$a_n=11+7n$

Therefore, the required expression for nth term of the sequence is $a_n=11+7n$.