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ERIC Number: EJ875466
Record Type: Journal
Publication Date: 2004
Pages: 11
Abstractor: As Provided
Reference Count: 0
ISSN: ISSN-0740-8404
Finding Equations of Tangents to Conics
Baloglou, George; Helfgott, Michel
AMATYC Review, v25 n2 p35-45 Spr 2004
A calculus-free approach is offered for determining the equation of lines tangent to conics. Four types of problems are discussed: line tangent to a conic at a given point, line tangent to a conic passing through a given point outside the conic, line of a given slope tangent to a conic, and line tangent to two conics simultaneously; in each case, a comparison to the standard calculus method is made by way of specific examples. Extending an idea of Descartes, this calculus-free approach is based on the fact that a quadratic has a double root if and only if its discriminant is equal to zero. It should be appropriate for both precalculus and calculus students.
American Mathematical Association of Two-Year Colleges. 5983 Macon Cove, Memphis, TN 38134. Tel: 901-333-4643; Fax: 901-333-4651; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Two Year Colleges
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A