Question

For problems 12 - 14, Determine whether each sequence appears to be an

arithmetic sequence. If so, find the common difference and the next three terms.

12. 1, 2, 3, 4, 5, ...

13. 3, 0, -3, -6, ...

14.2, 4, 6, 9, 11, ...

15. Find the 50th term if d = 5 and a = 10

Answer 1

Explanation:

⇒12)It is an arithmetic sequence.

d=2-1=3-2=4-3=1

a(n) = a +(n-1)d

a(n) = 1+(n-1)1

The next three terms:

a(6) = 1+(6-1)1=6

a(7) = 1+(7-1)1=7

a(8) = 1+(8-1)1=8

⇒13)It is an arithmetic sequence.

d=0-3=-3-0=-6+3=-3

a(n) = a +(n-1)d

a(n) = 3+(n-1)-3

The next three terms:

a(5) = 3+(5-1)-3=-9

a(6) = 3+(6-1)-3=-12

a(7) = 3+(7-1)-3=-15

⇒14)It is not an arithmetic sequence.

⇒15) a(50) = 10 +(50-1)5

=255

I hope this helps