Chapter 7, Problem 77SGR

To determine

The first five terms of a sequence.

Answer to Problem 77SGR

The first five terms are 11, 7, 3, -1, -5.

Explanation of Solution

Given information: Given first term $a_1=11$ , and also $a_n=a_{n-1}-4$ , $n\ge 2$ .

Calculation:

First term $a_1=11$ and given $a_n=a_{n-1}-4$ , $n\ge 2$ .

When n=2, second term

  $\begin{array}{l}{a}_2=a_1-4\\ =11-4\\ =7\end{array}$

When n=3, third term

  $\begin{array}{l}{a}_3=a_2-4\\ =7-4\\ =3\end{array}$

When n=4, fourth term

  $\begin{array}{l}{a}_4=a_3-4\\ =3-4\\ =-1\end{array}$

When n=5, fifth term

  $\begin{array}{l}{a}_5=a_4-4\\ =-1-4\\ =-5\end{array}$

So, the first five terms are 11, 7, 3, -1, -5.