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The probability certain random quadratics have real roots

Authors :
Chris Boucher
Source :
The Mathematical Gazette. 105:410-415
Publication Year :
2021
Publisher :
Cambridge University Press (CUP), 2021.

Abstract

Early in high school algebra, quadratics chosen as examples by teachers and textbooks alike tend to have integer coefficients and to factorise over the integers. This can give the misleading impression that such quadratics are the norm. As students progress into calculus and begin regularly seeing quadratics that are not as ‘nice’, we hope they become disabused of this notion. Indeed, even if the coefficients of the quadratic are integers, the probability that the quadratic factorises over the integers tends to zero as the range from which the integers are drawn grows (see [1]). But what if we ask about a behaviour less restrictive than factorising, say merely having real roots? This is the problem that concerns this Article.

Details

ISSN :
20566328 and 00255572
Volume :
105
Database :
OpenAIRE
Journal :
The Mathematical Gazette
Accession number :
edsair.doi...........3d015fbbbf766674ad16c592f0853ce2
Full Text :
https://doi.org/10.1017/mag.2021.107