College Mathematics Journal Contents—November 2014

The final College Mathematics Journal issue of volume 45 opens with Jeff Suzuki considering when a gerrymander goes awry into the realm of a dummymander. There are two articles on the popular game Nim: Lisa Rougetet examines the European recreations that preceded it, while Fillers, Linderman, and Simoson explore its connections to the game Mancala. Interspersed with a combinatorial proof, a statistics perspective on calculus, and new results on confocal conics are a record six Proofs Without Words. The cover art by Marc Frantz illustrates a "found math" example of a hyperbola with horizontal and vertical asymptotes detailed in his Classroom Capsule. The issue closes with citations for the George Pólya Awards given at MathFest and a list of the generous referees whose work is essential to the CMJ. —Brian Hopkins

Vol 45 no 5, pp 335-416

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ARTICLES

The Self-Limiting Partisan Gerrymander: An Optimization Approach

Jeff Suzuki

Applying optimization techniques to partisan gerrymandering yields profoundly disturbing results. If equipopulation is the only enforceable constraint, then an optimal redistricting would allow the party in control of the districting apparatus (the in-party) to produce a substantial disparity between the fraction of the total vote won by the party and the fraction of the legislative seats won by the party. Moreover, unrestricted partisan gerrymandering allows the in-party to engage in extremist politics without electoral consequences.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.338

Proof Without Words: Summing Squares by Counting Triangles

B. Nelsen

A visual proof of an identity for squares using the inclusion-exclusion principle.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.349

Mancala as Nim

Whitney Rhianna Fillers, Bill Linderman, and Andrew Simoson

We show that a simple version of Mancala is a somewhat camouflaged version of Nim and use game trees to analyze certain cases.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.350

Proof Without Words: An Arctangent Identity

Hasan Unal

A visual proof of an arctangent identity involving π.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.357

A Prehistory of Nim

Lisa Rougetet

The first occurrence of Nim dates back to 1901 when the mathematician Charles Leonard Bouton published an article on its solution. But what are the origins of the Nim game? This article offers a survey of European ancestors of Nim.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.358

Proof Without Words: Limit of a Recursive Arithmetic Mean

Ángel Plaza

Visual proof of the limit of a recursive arithmetic mean sequence.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.364

A Combinatorial Proof of a Theorem of Katsuura

Brian K. Miceli

We give a combinatorial proof of an algebraic result of Katsuura’s. Moreover, we use the proof of this result to shed some light on an interesting property of the result itself.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.365

Proof Without Words: Cosine Difference Identity

Long Wang

We give a visual proof of the cosine difference formula.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.370

Unfamiliar Properties of Familiar Shapes

Asya Shpiro

We present a surprising property of intersecting confocal conics: Their intersection points and the intersection point of their directrices are collinear. We give geometric proofs for various cases of two ellipses.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.371

Proof Without Words: A Sine Identity for Triangles

Roger B. Nelsen

We wordlessly prove a sine result for the angles of a triangle.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.376

Calculus from a Statistics Perspective

Kimberly Leung, Chris Rasmussen, Samuel S. P. Shen, and Dov Zazkis

We present a statistics perspective on calculus, which can help students understand calculus concepts and analyze a function defined by data or sampling values from a given function, rather than an explicit mathematical formula. Our approach uses the arithmetic and graphic means for the notions of integral and derivative, respectively. An intuitive approach to the law of large numbers replaces the notion of limit for this introductory level.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.377

Proof Without Words: A Formula of Hermann

Hasan Unal

A visual proof of a formula for π proved by the Swiss mathematician Jakob Hermann in 1706.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.387

Classroom Capsules

Hyperbola: Under Construction! 

Marc Frantz

We show how a perspective illusion in a picture of a building under construction leads to the design of a classical linkage for drawing a hyperbola.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.388

A Squeeze for Two Common Sequences That Converge to e

Branko Curgus

The note gives a simple proof that two common sequences, that are traditionally used to define the number e, converge to the same limit.

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.391

Problems and Solutions

Problems: 1036-1040
Solutions: 1002-1015

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.393

Book Review

Origins of Mathematical Words by Anthony Lo Bello

Reviewed by Brian Hopkins

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.400

Media Highlights

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.406

George Pólya Awards for 2014 and Referees in 2014

To purchase from JSTOR: http://dx.doi.org/10.4169/college.math.j.45.5.414