### 6Sequences and series

In this chapter we look at different patterns in sequences of numbers, and how they might be described. We discover how it is possible to find the sum of the terms of some of these sequences, and find some practical applications of these sums. We begin to see how infinite quantities of things behave through looking at what happens if we have very large numbers of them. Endless quantities of things have to be treated with great caution, so I show you some examples of what can happen otherwise.

The chapter is divided into the following sections.

**6.A Patterns and formulas**

(a) Finding patterns in sequences of numbers,

(b) How to describe number patterns mathematically

**6.B Arithmetic progressions (APs)**

(a) What are arithmetic ...