Question

An arithmetic sequence has this recursive formula:

A1=6
An=an-1-3
What is the explicit formula for this sequence?

Answer 1

A

Explanation:

Sn=a(n-1) d

this formula for Calculating arithmetic sequence

Answer 2

Answer: D.
`a_n=6+(n-1)(-3)`

Explanation:

Given : An arithmetic sequence has this recursive formula:

`a_1=6 \ \ \; \ a_n=a_(n-1)-3`

Using the given information, Second term of arithmetic sequence will be :-

`a_2=a_(1)-3=6-3=3`

That means common difference =
`a_2-a_1=3-6=-3`

The explicit formula for arithmetic sequence is given by :-

`a_n=a+(n-1)d`, where a is the first term and d is the common difference.

Put a= 6 and d= -3, we get

The explicit formula for this sequence :-

`a_n=6+(n-1)(-3)`