Question

The first five terms of an arithmetic sequence are 8, 13/2, 5, 7/2, and 2. Which function, f(x), could be used to describe the xth term of the sequence?

f(x)=?

Answer 1

Answer:

The nth term of the sequence is:

$a_n=\frac{-3n+3}{2}+8$

Step-by-step explanation:

Given the first 5 terms of the arithmetic sequence

8, 13/2, 5, 7/2, and 2

An arithmetic sequence has a constant difference 'd' and is defined by:

$a_n=a_1+\left(n-1\right)d$

as the common difference 'd' is:

$d=a_{n+1}-a_n$

Computing the differences of all the terms

$\frac{13}{2}-8=-\frac{3}{2},\:\quad \:5-\frac{13}{2}=-\frac{3}{2},\:\quad \frac{7}{2}-5=-\frac{3}{2},\:\quad \:2-\frac{7}{2}=-\frac{3}{2}$

$d=-\frac{3}{2}$

The first element is:

$a_1=8$

Therefore, the nth term is computed by:

$a_n=a_1+\left(n-1\right)d$

$a_n=-\frac{3}{2}\left(n-1\right)+8$

$a_n=\frac{-3n+3}{2}+8$

Therefore, nth term of the sequence is:

$a_n=\frac{-3n+3}{2}+8$