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ERIC Number: EJ818726
Record Type: Journal
Publication Date: 2008
Pages: 3
Abstractor: ERIC
Reference Count: 0
ISBN: N/A
ISSN: ISSN-0045-0685
The Ubiquitous Parabola
Hyde, Hartley
Australian Mathematics Teacher, v64 n3 p7-9 2008
Parabolic shapes are easy to find. Many homes outside the cable area have parabolic antennas to receive television transmissions from a satellite far out in space. Parabolic extrusions are used as reflectors behind fluorescent tubes and solar heated water pipes. Parabolic reflectors are used to build solar ovens, searchlights and radio telescopes. This article presents two work sheets: the first is designed for use with "Cabri Geometry" to study the parabola as a conic section and the second presents a similar construction for a circular paraboloid using "Cabri 3D." Both models show clearly that the parabolic locus will reflect incoming rays, that are parallel to the line of symmetry, back through the focus. This article also illustrates a use of the two "Cabri" products to study a 2D object before considering its 3D equivalent. "Cabri 3D V2" now allows one to insert measurements, equations and coordinates. It also allows one to trace the trajectory of a point or curve.
Australian Association of Mathematics Teachers (AAMT). GPO Box 1729, Adelaide 5001, South Australia. Tel: +61-8-8363-0288; Fax: +61-8-8362-9288; e-mail: office@aamt.edu.au; Web site: http://www.aamt.edu.au
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Grade 11; Secondary Education
Audience: Teachers
Language: English
Sponsor: N/A
Authoring Institution: N/A