Question

The first five terms of a sequence are 5, 4, 3, 2, 1. What is the explicit formula for the sequence?

A.
`an=n-6`
B.
`an=5-n`
C.
`an=6-n`
D.
`an=n-5`

Answer 1

C

Explanation:

Answer 2

The explicit formula for the sequence is:

Option: C

C.
`a_n=6-n`

Explanation:

We are given first five terms of a sequence as:

5,4,3,2,1

i.e. if
`a_n` represent the nth term of a sequence then we have:

`a_1=5\\\\a_2=4\\\\a_3=3\\\\a_4=2\\\\a_5=1`

Hence, the rule that follows for the terms of the sequence is:

C.
`a_n=6-n`

Since when n=1 we have:

`a_1=6-1\\\\a_1=5`

when n=2 we have:

`a_2=6-2\\\\a_2=4`

when n=3 we have:

`a_3=6-3\\\\a_3=3`

when n=4 we have:

`a_4=6-4\\\\a_4=2`

when n=5 we have:

`a_5=6-5\\\\a_5=1`