9893
EXPLORE
LATEST
ABOUT
AUTHORING AREA
PARTICIPATE
Your browser does not support JavaScript or it may be disabled!
A Visual Proof of the Double-Angle Formula for Sine
The double-angle formula for sine states that
. Computing the area of a triangle using the formula
(area equals one-half base times height) gives
for the top triangle and
for the bottom triangle.
Contributed by:
Chris Boucher
SNAPSHOTS
DETAILS
This image is from J. D. Currie, "Proof without Words: Double Angle Formula via Area,"
Mathematics Magazine
,
81
(1), 2008 p. 62.
RELATED LINKS
Double-Angle Formulas
(
Wolfram
MathWorld
)
PERMANENT CITATION
"
A Visual Proof of the Double-Angle Formula for Sine
" from
the Wolfram Demonstrations Project
http://demonstrations.wolfram.com/AVisualProofOfTheDoubleAngleFormulaForSine/
Contributed by:
Chris Boucher
Share:
Embed Interactive Demonstration
New!
Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site.
More details »
Download Demonstration as CDF »
Download Author Code »
(preview »)
Files require
Wolfram
CDF Player
or
Mathematica
.
Related Demonstrations
More by Author
Difference Formula for Cosine
Chris Boucher
Cofunction Identities for Sine and Cosine
Chris Boucher
Two Visual Proofs of a Basic Trigonometric Identity
Izidor Hafner
Squares of Sine and Cosine
Izidor Hafner
Dissection Proof of the Addition Formula for Sines
Izidor Hafner
Cosine and Sine of the Sum of Two Angles
Tomas Garza
Trisecting an Angle Using a Lemniscate
Izidor Hafner
Wrapping the Number Line around the Unit Circle
Marc Brodie (Wheeling Jesuit University)
Polar Angles and Points on the Unit Circle
Izidor Hafner
Minimum Area between a Semicircle and a Rectangle
Abraham Gadalla
Related Topics
Plane Geometry
Trigonometric Functions
High School Algebra II and Trigonometry
High School Mathematics
Browse all topics
Note: To run this Demonstration you need Mathematica 7+ or the free Mathematica Player 7EX
Download or upgrade to
Mathematica Player 7EX
I already have
Mathematica Player
or
Mathematica 7+