Question

Describe and correct the error a student made in identifying the common difference of the following sequence.

Answer 1

Given:

The sequence is 29, 22,​ 15, 8,​ 1, ...

To find:

The common difference.

Solution:

We have,

29, 22,​ 15, 8,​ 1, ...

It is an AP.

First term : $a_1=29$

Second term : $a_2=22$

Now,

Common difference : $d=a_2-a_1$

$d=22-29$

$d=-7$

Therefore, the correct common difference is -7.

Note: Here calculation by student is not given, so we cannot find the error of the student.