Chapter SH, Problem 10.21EP

To determine

To find:The recursive formula for given sequence.

Answer to Problem 10.21EP

The recursion formula is $a_n=a_{n-1}-2,a_5=-4$ .

Explanation of Solution

Given: The given sequence is $a_5=-4,d=-2$ .

Consider the sequence,

  $a_5=-4,d=-2$ ...... (1)

The sequence is an arithmetic progression with common difference as -2.

The recursion formula for the AP is given by,

  $\begin{array}{c}{a}_n=a_{n-1}+d\\ a_n=a_{n-1}-2\end{array}$

And,

  $a_5=-4$

Therefore, the recursion formula is $a_n=a_{n-1}-2,a_5=-4$ .