Oswego City School District
Regents Exam Prep: Angle Sum & Difference, Double Angle
The mathematics session examines angle sum, angle difference, double angle, and half angle formulas. The tutorial includes class notes, examples, and practice problems with solutions. The teacher resource investigates how the formulas...
Illustrative Mathematics
Illustrative Mathematics: F Tf Sum and Difference Angle Formulas
The goal of this task is to have learners derive the addition and subtraction formulas for cosine and tangent, and the subtraction formula for cosine, from the sum formula for sine. Aligns with F-TF.C.9.
Khan Academy
Khan Academy: Find Trig Values Using Angle Addition Identities
Find the trigonometric values of various angles that (while they are not special angles) can be expressed as the sum or difference of special angles. Students receive immediate feedback and have the opportunity to try questions...
Windstream
Ojk's Precalculus Study Page: Double and Half Angle Formulas
This tutorial introduces the double-angle and half-angle formulas for sine, cosine, and tangent, and gives sample application and proof exercises. Assumes knowledge of the sum and difference formulas.
Other
Mathway: Trigonometry Formulas
Resource provides trigonometry formulas for unit circle, reciprocal identities, ratio identities, Pythagorean identities, sum and difference formulas, and double-angle formulas.
Other
Sierra College: Trigonometric Identities
Provides trigonometric identities, which include fundamental identities, even-odd identities, addition formulas, double-angle formulas, subtraction formulas, product-sum formulas, and identities for sin squared and cos squared.
Lawrence Hall of Science
The Math Page: Trigonometry: Trigonometric Identities
This resource clearly and thoroughly explains the many types of trigonometric identities. There are example problems solved, problems for the student to attempt, and answers to the student problems.
Math Words
Math words.com: Trig Identities
This MathWords.com site lists the equations for all of the trigonometric identities.