Martha Candler

Welcome to Trigonometry on!

How to Use This Course

The Trigonometry course on is presented as a supplemental Trigonometry course. The topics cover the ideas and topics that are basic in working with Trigonometry. Right angles, acute angles, graphing, inverse functions, solving trigonometric equations, and more are covered in this supplemental course. Worksheets and answer keys are included. These lessons are best covered in the order they are given if this course is being used as a complete review of Trigonometry. If only certain topics need to be reviewed, each topic can be chosen from the lessons shown and reviewed as necessary.

Course Details

Course Introduction

Welcome to the Trigonometry course. I’m Martha Candler, and I look forward to helping you in the days and weeks to come.

I have chosen to explain in detail the basic topics in a course that is part of the Algebra II sequence, as well as an introduction to additional topics for students in the Pre-Calculus sequence. You will need additional problems to work and an extension of these ideas at times. Just keep in mind that it is not my intent to provide you with a complete course as in a textbook—although it comes close to that on certain topics. Graphing calculator use is explained briefly for certain problems.

A table of contents is included so that you can tell which topics are covered in our 14 weeks of lessons.

Along the way, I have numerous problem sheets and answer keys in my lessons.

Thank you for attempting this course and joining me here at I hope it has been helpful. I would appreciate it very much if you let me know which parts were the most helpful. Just send a message to

— Martha Candler


Written instruction, helpful illustrations, practice exercises, answer keys, and additional resources for further learning


14 weekly lessons


High school

Course Outline

  • Week 1: Right Triangle Trigonometry
  • Week 2: From Acute Angles to Any Angles
  • Week 3: From Any Angle to All Real Numbers
  • Week 4: Graphing the Sine and Cosine Functions
  • Week 5: More Graphing and Inverse Functions
  • Week 6: Working with Identities
  • Week 7: Verifying Identities
  • Week 8: Solving Trigonometric Equations
  • Week 9: More Trigonometric Equations and Using New Identities
  • Week 10: The Last Identities
  • Week 11: Oblique Triangles and the Law of Sines
  • Week 12: The Law of Cosines and Using Vectors
  • Week 13: Trigonometric Form of a Complex Number
  • Week 14: The Polar Coordinate System

Download the Trigonometry syllabus here.

Download a Preview

View a sample of the Trigonometry class.

Course Completion Certificates

Go to all of the Trigonometry lessons.

Martha Candler photo

Martha Candler is a mathematics teacher with five years of high school experience and 20 years of teaching math at the college level, most often as an adjunct instructor so that she could be home when her children were home. With most of her experience in College Algebra, Trigonometry, Pre-Calculus, and Business Calculus, her favorite has always been Trigonometry.

She believes that students should understand what they do and not just do the work mechanically or through shortcuts. As much as possible, they should see a reason or use for what they are learning. This is her philosophy when creating extra materials for her classes.

Martha has two married daughters who went through public schools, but that might not be the case if they were school age now, she says. She enjoys reading, needlework, and is very involved in the music program at her church, where she plays piano, keyboard, harp (occasionally), and works with a men’s vocal quintet and a mixed ensemble.

You can see some of her created materials on

Trigonometry course on Schoolhouse Teachers