CK-12 Foundation
Double Angle Identities: Ferris Wheel
Use a Ferris wheel to soar to new heights of understanding on double angle identities. Here is an interactive that applies an example of a Ferris wheel to show how doubling the angle does not double the value of a trigonometric ratio....
Curated OER
Math Handbook: Trigonometry
You'll be spinning in unit circles once you read through this jumbo-sized resource of everything you need to know about trigonometry. Each page has color-coded examples with explicit directions that detail the problems and...
EngageNY
Addition and Subtraction Formulas 2
Knowing the addition formulas allows for the calculations of double and half formulas. The fourth installment of 16 has the class use the addition formula to develop the double angle trigonometric formulas. Using the double formula,...
Curated OER
Trigonometry Worksheet: Double Angle Formula (1)
Students use the double angle formula to solve one problem. They are given the problem: if sin(a)=3/5, and a is an acute angle, use the double angle formula to find exact values of given sin, cosign, and tangent within the quadrant of...
Curated OER
Angle Sum and Difference
For this angle sum and difference worksheet, 11th graders solve 10 different problems related to determining the angle sum and difference of numbers. First, they determine the exact value of sine and cosine degrees. Then, students...
Curated OER
Trigonometric Identities
For this trigonometry worksheet, students solve and analyze the reciprocal, quotient, Pythagorean and Cofunction Identities. They also discuss sum and difference identities, double angle and half angle identities.
Curated OER
Trigonometry - Week 9
In this trigonometry worksheet, young scholars use the sum-to-product formula, and the law of sines and cosines to solve trigonometry problems. This two-page worksheet contains eight problems.
EngageNY
Mid-Module Assessment Task: Pre-Calculus Module 4
Challenge scholars to show what they know about properties and addition and subtraction formulas for trigonometric functions. The resource provides a mid-unit check on the progress toward mastery of trigonometric concepts. The areas...
CK-12 Foundation
Ck 12: Trigonometry: Double Angle Identities
[Free Registration/Login may be required to access all resource tools.] Derivation of double angle identities for sine, cosine, and tangent.
Wolfram Research
Wolfram Math World: Double Angle Formulas
Part of Eric Weisstein's comprehensive math site, this page deals with double-angle formulas. This site includes traditional trigonomic double-angle functions as well as hyperbolic trigonometric function. Includes links to related terms...
Math Medics
S.o.s. Math: Double Angle and Half Angle Formulas
Double angles and half angles are explained through step by step examples. The steps are clear and easy to follow.
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.
Northeast Parallel Architectures Center, Syracuse University
Npac Reu Program: Trigonometry Review
The Northeast Parallel Architectures Center, Syracuse University, provides a review and tutorial site on trigonometry. The information is in-depth and can be accessed by clicking on the various links in the outline.
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.
University of Saskatchewan (Canada)
University of Saskatchewan: Trigonometric Identities
The University of Saskatchewan provides an explanation of trigonometric identities, including the reciprocal identities, the addition and subtraction formulas with sine and cosine, and the double angle formulas. There are links to...
Math Medics
S.o.s. Math: Trigonometry
This lesson is the main SOS Math page for trigonometry. Surf the lesson to find most any trigonometric identity, formula, and many forms of help in the area of trigonometry.
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.
Other
Brown Math: Remembering Trig Identities
Faced with a large number of trigonometric identities, students tend to try to memorize them all. This site the emphasis is on understanding how the functions work and on memorizing only about a half dozen of them - all the others work...
Math Words
Math words.com: Trig Identities
This MathWords.com site lists the equations for all of the trigonometric identities.