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Inflection Points of Bessel Functions of Negative Order

Published online by Cambridge University Press:  20 November 2018

Lee Lorch
Affiliation:
Department of Mathematics and Statistics, York University, North York, Ontario M3J 1P3
Martin E. Muldoon
Affiliation:
Department of Mathematics and Statistics, York University, North York, Ontario M3J 1P3
Peter Szego
Affiliation:
75 Glen Eyrie Ave., San Jose, California 95125, USA
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Abstract

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We consider the positive zeros jvk, k = 1, 2,…, of the second derivative of the Bessel function Jν(x). We are interested first in how many zeros there are on the interval (0,jν1), where jν1 is the smallest positive zero of Jν(x). We show that there exists a number ƛ = —0.19937078… such that and . Moreover, jv1 decreases to 0 and jν2 increases to j01 as ν increases from ƛ to 0. Further, jvk increases in —1 < ν< ∞, for k = 3,4,… Monotonicity properties are established also for ordinates, and the slopes at the ordinates, of the points of inflection when — 1 < ν < 0.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1991

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