CK-12 Foundation
Finding Exact Trigonometric Values Using Double Angle Identities: Trig Values Using Double and Half Angle Formulas
The more you know, the more you can learn. Scholars apply the double angle and half angle formulas to determine trig values based on known values. They use an interactive that provides sine and cosine values to aid calculations.
CK-12 Foundation
Half Angle Formulas: Half-Angle Formulas
Slide the resource into your lesson plans. Young mathematicians use a slider to move a movie screen to the right position for optimal viewing. Along the way, they learn to apply the half angle formulas.
Curated OER
Half Angle Formula
In this half angle formula worksheet, students use half angle formulas to find the value of given angles. This one-page worksheet contains 1 multi-step problems.
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,...
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...
Curated OER
Trigonometric Identities
In 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
Interior and Exterior Angles of Polygons
In this angles of polygons worksheet, 10th graders solve and complete 18 different problems that include determining various interior and exterior angles. First, they determine the measure of various angles described in the first half of...
Curated OER
Angle Sum and Difference
In this angle sum and difference instructional activity, 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,...
Illustrative Mathematics
Seven Circles III
A basic set-up leads to a surprisingly complex analysis in this variation on the question of surrounding a central circle with a ring of touching circles. Useful for putting trigonometric functions in a physical context, as well as...
Curated OER
Integrals with Even Powers of Sine and Cosine
Students discuss ways to integrate given trigometric functions. They use a trig identity (half angle identities) to solve problems. Students practice solving problems with even powers of both sine and cosine. They change a sum of...
Curated OER
Identities and Trigonometric Values
Students solve trigonometric equations. In this precalculus lesson, students prove trigonometric identities using the Pythagorean Theorem. They apply the addition formulas for sine and cosine to prove different identities.
EngageNY
Using Trigonometry to Determine Area
What do you do when you don't think you have enough information? You look for another way to do the problem! Pupils combine what they know about finding the area of a triangle and trigonometry to determine triangle area when they don't...
Curated OER
Physics Lab Rockets
Students construct and test balloon rockets and a model rocket. In this rocket science lesson, students use an inquiry-based method to master balloon rockets and have a shoot-off with the goal of attaining the highest altitude. Next,...
Curated OER
Trigonometric Functions
In this trigonometric functions worksheet, students solve and complete 35 various type of problems. First, they find the values for all six trig functions that pass through the given points. Then, students prove different identities as...
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...
Curated OER
Chapter 6: Geometry Perimeter and Area
In this perimeter and area activity, students find the perimeter of various polygons. They compute the perimeter, surface area, circumference, and volume of given figures. Students explore trigonometric ratios. This...
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.
Wolfram Research
Wolfram Math World: Half Angle Formulas
This page, from Eric Weisstein's comprehensive Math World site, offers information on half-angle formulas. The site includes traditional trigonometric fuctions half-angle formulas as well as hyperbolic half-angle formulas. Includes links...
CK-12 Foundation
Ck 12: Trigonometry: Half Angle Formulas
[Free Registration/Login may be required to access all resource tools.] Using identities to derive more half angle formulas.
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.
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
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...
Massachusetts Institute of Technology
Mit: Useful Trigonometric Identities
This list of trigonometric identities includes the factoring formulas near the bottom. A great tool for reference.
Math Words
Math words.com: Trig Identities
This MathWords.com site lists the equations for all of the trigonometric identities.