10. An arithmetic
sequence is a sequence
where every term after
the first is obtained by
adding a constant called
the common difference.
11. The sequences
1,4,7,10,... and 15, 11, 7,
3,... are examples of
arithmetic sequences since
each one has a common
difference of 3 and -4.
12. Arithmetic Rule
an= a1+(n - 1)d
•a1 is the first term in the sequence
•n is the number of the term you are
trying to determine
•d is the common difference
•an is the value of the term that are
looking for
13. Try this…
Use the arithmetic formula to
determine the 100th term of
the following sequence:
75, 25, -25, -75, -125,…
14. an = a1 + (n - 1)d
= 75 + (100 – 1)(-50)
= -4875a1 = 75
n = 100
d = -50
15. Try this…
Use the arithmetic formula to
determine the 10th term of
the following sequence:
5, 12, 19, 26,…
16. an = a1 + (n - 1)d
= 5 + (10 – 1)(7)
= 68a1 = 5
n = 10
d = 7