Envelope

Pronunciation: /ˈɛn vəˌloʊp/ Explain

Animated image showing the creation of an envelope from a family of lines.
Figure 1: Creation of an envelope.

In mathematics, an envelope is a curve that is tangent to a family of lines or other geometric shapes.[1] Figure 1 shows the creation of an envelope from a family of lines. Manipulative shows two blue lines that are envelopes for a family of circles. Click on the blue points in manipulative 1 and drag them to change the figure.

Click on the blue points and drag them to change the figure.

What would the circles look like if the two blue envelope lines were concurrent?
Manipulative 1 - Envelope of Circles Created with GeoGebra.

Cite this article as:

McAdams, David E. Envelope. 7/9/2018. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/e/envelope.html.

Image Credits

Revision History

7/5/2018: Removed broken links, updated license, implemented new markup, implemented new Geogebra protocol. (McAdams, David E.)
1/24/2010: Added "References". (McAdams, David E.)
11/18/2008: Changed manipulative to GeoGebra. (McAdams, David E.)
5/10/2008: Initial version. (McAdams, David E.)

All Math Words Encyclopedia is a service of Life is a Story Problem LLC.
Copyright © 2018 Life is a Story Problem LLC. All rights reserved.
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License