A LevelMathsEdexcelPureRevision NotesTrigonometryReciprocal & Inverse Trigonometric FunctionsDefinitions of Reciprocal Trigonometric Functions

Definitions of Reciprocal Trigonometric Functions (Edexcel A Level Maths: Pure): Revision Note

Exam code: 9MA0

Written by: Roger B

Reviewed by: Dan Finlay

Updated on 2 July 2026

Definitions of reciprocal trigonometric functions

What are the reciprocal trigonometric functions?

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

Recip-Trig-Functs-Defs, A Level & AS Maths: Pure revision notes

Cotangent can also be written in terms of sine and cosine

Recip Trig Functs Cotan, A Level & AS Maths: Pure revision notes

Examiner Tips and Tricks

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.

Worked Example

Recip Trig Functs Example, A Level & AS Maths: Pure revision notes

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Author: Roger B

Expertise: Development Editor

Roger's teaching experience stretches all the way back to 1992, and in that time he has taught students at all levels between Year 7 and university undergraduate. Having conducted and published postgraduate research into the mathematical theory behind quantum computing, he is more than confident in dealing with mathematics at any level the exam boards might throw at you.

Reviewer: Dan Finlay

Expertise: Portfolio Lead

Dan graduated from the University of Oxford with a First class degree in mathematics. As well as teaching maths for over 8 years, Dan has marked a range of exams for Edexcel, tutored students and taught A Level Accounting. Dan has a keen interest in statistics and probability and their real-life applications.