# AQA A Level Maths: Pure复习笔记5.5.1 Reciprocal Trig Functions - Definitions

### Reciprocal Trig Functions - Definitions

#### What are the reciprocal trigonometric functions?

• There are three reciprocal trig functions corresponding to the three regular trig functions

• Cotangent can also be written in terms of sine and cosine

#### Exam Tip

• To solve equations with the reciprocal trig functions, convert them into the regular trig functions and solve in the usual way.
• Don't forget that both tan and cot can be written in terms of sin and cos (see the Worked Example below).
• You will sometimes see csc instead of cosec for cosecant.