Sequences (Edexcel IGCSE Maths A (Modular))

A sequence is an ordered set of (usually) numbers.

A term is one of the numbers in a sequence.

n is the position of a term in a sequence.

E.g. when n = 3, it is referring to the third term of the sequence.

False.

For the first term, n = 1.

Subscript notation is used to talk about a particular term.

For example

• is the 1st term

• is the 7th term

• is the nth term

A position-to-term rule gives the nth term of a sequence as a formula in terms of n.

To find the first three terms of a sequence using a position-to-term rule, substitute , and into the position-to-term formula.

A term-to-term rule tells you how to find a term from the term before it.

I.e., it gives the (n+1)th term in terms of the nth term.

An arithmetic sequence is a sequence of numbers that increase or decrease by the same amount from one term to the next.

The common difference is the amount that an arithmetic sequence increases or decreases by from one term to the next.