INTRODUCTION

Scientists, engineers, and other professionals work with radians in many ways. For example, the variety of sounds possible in electronic music is created using trigonometric models. Also, the electricity produced by a power plant follows a trigonometric relation. In this chapter, we will learn about Cast Rule, how to determine exact trigonometric ratios of special angles, angles in standard position.

Trigonometric comes from two greek terms,

trigon

meaning triangle and

mentron

meaningmeasure. so, trigonometric is the study of triangle measurement.

Trigonometric Ratios

The most common trigonometric ratios are

sine

,

cosine

, and

tangent.

Sine= opposite/ hypotenuse

Cosine= adjacent/ hypotenuse

Tangent= opposite/ adjacent

ANGLES IN STANDARD POSITION

An angles is in

STANDARD POSITION

when it is centred at the origin,

the initial arm is the positive x-axis and the terminal arm rests

anywhere within the four quadrants.

Unit Circle

How to determine trigonometric ratios with special angles.

**4.2 Trigonometric Ratios and special angles.**

By: Akanbi Ololade .F.

Objectives:

Define angles in standard position

State Cast Rule

Unit circle

How to determine trigonometric ratios with special angles

Solving Problems

By: Akanbi Ololade .F.

Objectives:

Define angles in standard position

State Cast Rule

Unit circle

How to determine trigonometric ratios with special angles

Solving Problems

This video shows how to find the trigonometric ratios of the special angles and how to use them to find exact values of expressions.

Table of values of the 6 trigonometric functions

sin x, cos x, tan x, cot x, sec x

,

and

csc x

for special angles.

N.B The letter

U

means

undefined.

Example: 3

Example: 4

Conclusion

Trigonometric is the study of relationship between the sides and angles of a triangle. the ratios of the sides in a right triangle with respect to its acute angles are called trtigonometric ratios of the angles.

Reference

McGraw-Hill Ryerson. (2008).

Advanced Functions

. Canada. Linda Allison Hsmathangccs 3. (2011). Unit 8a trigonometric. Retrieved from http: // www.google.ca/hsmathangcc.wiki.hci.edu.sg