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Trigonometry For Dummies, 3rd Edition
book

Trigonometry For Dummies, 3rd Edition

by Mary Jane Sterling
March 2023
Beginner content levelBeginner
400 pages
9h 38m
English
For Dummies
Content preview from Trigonometry For Dummies, 3rd Edition

Chapter 11

Operating on Identities

IN THIS CHAPTER

Bullet Adding sums of angles to your identity list

Bullet Subtracting angles with the difference identities

Bullet Doubling angle values

Bullet Taking half an angle

The basic building-block identities are the reciprocal, ratio, opposite angle, and Pythagorean identities, which I discuss in detail in Chapter 10. In this chapter, you take those identities a step further and develop new identities, discovering how to add, subtract, multiply, and divide the trig functions — in particular, the nice values for angles of 0, 30, 45, 60, and 90 degrees. (Those angles aren’t the only ones that you can perform operations on; they’re just the most convenient to use when showing how the trig identities work.) By performing such operations, you can determine the function values of even more angles than before. Whole new worlds will open up to you!

Summing It Up

The sums of angles are covered by three basic identities; these identities involve sine, cosine, and tangent. After you recognize these three identities, you can adapt them for the other three functions (cosecant, ...

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Publisher Resources

ISBN: 9781394168552Purchase Link