Question

Write the first five terms of the arithmetic sequence. a1 = 9; d = -2

Answer 1

Answer:

nth term = 1 1/2n -1

Step-by-step explanation:

The arithmetic sequence formula is:

a n = a 1 + ( n – 1 ) d

Where: a n

is the nth term in the sequence

a 1

is the first term in the sequence

n

is the term you are solving for

d

is the common difference for any pair of consecutive numbers in the sequence.

First Term or  

n = 1 :

This is given in the problem.

a 1  =  9

Second Term or  

n = 2 :

Substitute  

2  for  n

in the formula and substitute the values from the problem giving:

a 2 = 9 + ( ( 2 – 1 ) × -2 )

a 2 = 9 + ( 1 × -2 )

a 2 = 9 +-2

a 2 = 7

Fifth Term or  n = 5 :

Substitute      in the formula and substitute the values from the problem giving:

a 5 = 9+ ( ( 5– 1 ) × -2 )

a 5 = 9 + ( 4 × -2 )

a 2 = 9 + -8

a 2 = 1  

Using this same process you should be able to determiner the

Third Term or  n = 3

: and Fourth Term or  n = 4 :