# Chapter 7: Trigonometric Functions and their Derivatives

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## Introduction

We define the sine to be 0 at argument 0, to have as derivative the sine
of the complement to its argument (This is half a right angle minus the original
argument), and extend differentiation to functions constructed from trigonometric
functions. Some other related functions are introduced.

## Topics

7.1 Sines and Cosines and their Derivatives