1. The Rule of a Series
Lesson # 30

2. The Rule of a Series The rule of a series allows you to:
Describe a series
Calculate a term based on its rank
Ex. Term = 5 x rank + 7
t = 5n + 7

3. Variables are represented by symbols.
These symbols are generally letters.
Ex. t = 4n + 3
Where t is the variable representing the value of one term
n represents the value of the rank
4n = 4 x n

4. Rule of an arithmetic progression:
Term = (common difference) x rank + number
Number = 1st term – common difference

5. Example In the series: 45, 49, 53, 57, … The common difference = 4
The number = first term – common difference
= 45 – 4 = 41
The Rule:
t = 4n + 41
What is the 5th term of this series?
t = 4(5) + 41 =
= 61

6. Example: Rank (n) Term (t) 1 11 2 14 3 17 4 20 What is the rule?
Common difference= 3
Number= 11-3 =8
rule: t=3n+8
What is the 5th term?

7. Home work
Pg 137
#1,2,6,7
Pg 138#8,9
Pg 139 #12