# Ch 13: Holt McDougal Algebra 2 Chapter 13: Trigonometric Functions

### About This Chapter

## How it works:

- Identify the lessons in the Holt McDougal Algebra 2 Trigonometric Functions chapter with which you need help.
- Find the corresponding video lessons within this companion course chapter.
- Watch fun videos that cover the trigonometric functions topics you need to learn or review.
- Complete the quizzes to test your understanding.
- If you need additional help, rewatch the videos until you've mastered the material or submit a question for one of our instructors.

## Students will learn:

- Right-angle trigonometry
- Special right angles, ratios and similarity
- Unit circles
- Conversion between radians and degrees
- Inverses of trigonometric functions
- Laws of sines and cosines
- Heron's formula in geometry

*Holt McDougal is a registered trademark of Houghton Mifflin Harcourt, which is not affiliated with Study.com.*

### 1. Special Right Triangles: Types and Properties

Not all right triangles are the same. In this lesson, we'll look at two special right triangles (30-60-90 and 45-45-90) that have unique properties to help you quickly and easily solve certain triangle problems.

### 2. Trigonometric Ratios and Similarity

Where do terms like sine, cosine and tangent come from? In this lesson, we'll learn about how similarity with right triangles leads to trigonometric ratios.

### 3. Practice Finding the Trigonometric Ratios

So you know what sine, cosine and tangent are. Great! But how do you use them? Find out how in this lesson as we find missing sides and angles using trigonometric ratios.

### 4. Problem-Solving with Angles of Elevation & Depression

In this lesson, you'll explore the difference between angles of elevation and depression. You'll also learn how to solve problems related to angles of elevation and depression using basic trigonometric relationships

### 5. Other Trigonometric Functions: Cotangent, Secant & Cosecant

After watching this video lesson, you will understand how the trigonometric functions cotangent, secant, and cosecant are related to the sine, cosine, and tangent functions.

### 6. Coterminal Angles: Definition & Examples

This lesson defines coterminal angles measured in degrees. You will learn how to calculate positive and negative coterminal angles with a few examples.

### 7. Using Unit Circles to Relate Right Triangles to Sine & Cosine

The unit circle is a helpful tool for understanding trigonometric concepts. In this lesson, we'll look at right triangles on the unit circle to better grasp sine and cosine.

### 8. Unit Circle: Memorizing the First Quadrant

Memorizing the unit circle can be a daunting task, but this lesson will show you a pattern to help you memorize the points, degree measures, and radian measures for the entire first quadrant.

### 9. Converting Between Radians and Degrees

Angles can be measured in degrees or radians. This lesson will explore the difference and provide you with a simple calculation that can be used to convert degrees into radians and radians into degrees.

### 10. Reference Angles & the Unit Circle

Watch this video lesson to learn how you can use the unit circle and its reference angles to help you solve trigonometry problems. Learn how to find your answers from the unit circle.

### 11. How to Solve Trigonometric Equations for X

Adding trigonometric functions into standard algebra equations adds complexity. Learn how to solve trigonometric equations for x and how to use inverse operations to simplify equations.

### 12. Properties of Inverse Trigonometric Functions

After watching this video lesson, you will understand why our inverse trigonometric functions have a limited range. Learn what this does. Also learn the notation for these functions.

### 13. Law of Sines: Definition and Application

Don't get stuck trying to find missing sides or angles in a triangle. Use the Law of Sines to rescue you from any perilous triangle in which you have just a few pieces of information.

### 14. Using Sine to Find the Area of a Triangle

Since you first started working with triangles in math class, chances are you've been exposed to the formula for the area of a triangle. However, that is only good if you know the height of the triangle. This lesson shows you how to get around that.

### 15. The Ambiguous Case of the Law of Sines

You might think that all math in very concrete, that an answer or a law is always right. But this is not always so. See, in certain situations, the law of sines actually give you two answers.

### 16. Law of Cosines: Definition and Application

In this lesson, we'll learn how to solve problems involving three sides and one angle in a triangle. The Law of Cosines, a modification of the Pythagorean Theorem, will save the day.

### 17. Using Heron's Formula in Geometry

Heron's formula has been around for a couple thousand years. Watch this video lesson to see how you can use Heron's formula to find the area of a triangle while only knowing the side lengths.

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### Other Chapters

Other chapters within the Holt McDougal Algebra 2: Online Textbook Help course

- Holt McDougal Algebra 2 Chapter 1: Foundations for Functions
- Holt McDougal Algebra 2 Chapter 2: Linear Functions
- Holt McDougal Algebra 2 Chapter 3: Linear Systems
- Holt McDougal Algebra 2 Chapter 4: Matrices
- Holt McDougal Algebra 2 Chapter 5: Quadratic Functions
- Holt McDougal Algebra 2 Chapter 6: Polynomial Functions
- Holt McDougal Algebra 2 Chapter 7: Exponential and Logarithmic Functions
- Holt McDougal Algebra 2 Chapter 8: Rational and Radical Functions
- Holt McDougal Algebra 2 Chapter 9: Properties and Attributes of Functions
- Holt McDougal Algebra 2 Chapter 10: Conic Sections
- Holt McDougal Algebra 2 Chapter 11: Probability and Statistics
- Holt McDougal Algebra 2 Chapter 12: Sequences and Series
- Holt McDougal Algebra 2 Chapter 14: Trigonometric Graphs and Identities