How_To_Be_Good_At_Math

306 ALGEBRA •^ FORMULAS AND SEQUENCES

Formulas and sequences

A sequence is a list of numbers that follows a pattern (see pages 14-17).

By using a formula to write a rule for a sequence, we can work out the

value of any term in the sequence without having to write out the whole list.

2 4 6

In this sequence,

each term is 2 more

than the previous term

1st term 2nd term 3rd term 4th term 5th term 6th term

Number patterns

A number sequence follows a particular pattern, or rule.

Each number in a sequence is called a term. The first number

in a sequence is called the first term, the second number is

called the second term, and so on.

(^81012)
+2 +2 +2 +2 +2
The nth term
In algebra, the value of an unknown term in a sequence is
known as the nth term – the “n” stands for the unknown
value. We can write a formula called a general term of
the sequence to work out the value of any term. The unknown term is
called the nth term
...
2 4 6 8 10
1st term 2nd term 3rd term 4th term 5th term nth term
The dots show
that the sequence
goes on forever
+2 +2 +2 +2
?
306-307_Sequence_and_Formula.indd 306 29/02/2016 16:39