Hans Humenberger

This book explores the versatile concept of maxima and minima — extremes and optimal values — across a broad spectrum of mathematics. Far from being limited to calculus, the concept of extremes is applicable to nearly every field of mathematics, including geometry, arithmetic, algebra, and stochastics, offering powerful tools for problem solving.The first part of the book introduces a wide range of applications of the method of extremes, showing how it can be used to tackle problems both in everyday life and in mathematical contexts. The second, larger part focuses on solving extreme value problems without relying on derivatives, instead building reasoning and proof from first principles. Here, special emphasis is placed on geometry, where questions of optimality often reveal surprising insights about shapes and figures. By approaching mathematics through the lens of extremes, readers will gain a deeper understanding of core concepts and discover fresh ways to enrich both learning and teaching.

This book explores the versatile concept of maxima and minima — extremes and optimal values — across a broad spectrum of mathematics. Far from being limited to calculus, the concept of extremes is applicable to nearly every field of mathematics, including geometry, arithmetic, algebra, and stochastics, offering powerful tools for problem solving.The first part of the book introduces a wide range of applications of the method of extremes, showing how it can be used to tackle problems both in everyday life and in mathematical contexts. The second, larger part focuses on solving extreme value problems without relying on derivatives, instead building reasoning and proof from first principles. Here, special emphasis is placed on geometry, where questions of optimality often reveal surprising insights about shapes and figures. By approaching mathematics through the lens of extremes, readers will gain a deeper understanding of core concepts and discover fresh ways to enrich both learning and teaching.

Geometry is one of the most beautiful aspects of mathematics. This beauty is because you can 'see' geometry at work. Most people are exposed to the very basic elements of geometry throughout their schooling with the most concentrated study in the secondary school curriculum. High schools in the United States offer one year of concentrated study of geometry that shows students how a mathematician functions, since everything that is accepted beyond the basic axioms must be proved. Unfortunately, as the course is only one year long, there is still very much in geometry left unexplored for the general audience. That is the challenge of this book, in which we will present a plethora of amazing geometric relationships.We begin with the special relationships of the Golden Ratio, before considering unexpected concurrencies and collinearities. Next, we present some surprising results that arise when squares and similar triangles are placed on triangle sides, followed by a discussion of concyclic points and the relationships between circles and various linear figures. Moving on to more advanced aspects of linear geometry, we consider the geometric wonders of polygons. Finally, we address geometric surprises and fallacies, before concluding with a chapter on the useful concept of homothety, which is not included in the American year-long course in geometry.

Geometry is one of the most beautiful aspects of mathematics. This beauty is because you can 'see' geometry at work. Most people are exposed to the very basic elements of geometry throughout their schooling with the most concentrated study in the secondary school curriculum. High schools in the United States offer one year of concentrated study of geometry that shows students how a mathematician functions, since everything that is accepted beyond the basic axioms must be proved. Unfortunately, as the course is only one year long, there is still very much in geometry left unexplored for the general audience. That is the challenge of this book, in which we will present a plethora of amazing geometric relationships.We begin with the special relationships of the Golden Ratio, before considering unexpected concurrencies and collinearities. Next, we present some surprising results that arise when squares and similar triangles are placed on triangle sides, followed by a discussion of concyclic points and the relationships between circles and various linear figures. Moving on to more advanced aspects of linear geometry, we consider the geometric wonders of polygons. Finally, we address geometric surprises and fallacies, before concluding with a chapter on the useful concept of homothety, which is not included in the American year-long course in geometry.

Dieses Lehrbuch unterstützt bei der Vorbereitung eines reizvollen, lebendigen und problemorientierten Geometrieunterrichts in der Primarstufe und Sekundarstufe I. Es macht die entsprechenden Sachverhalte der Elementargeometrie zugänglich und erlebbar, indem geometrische Figuren beschrieben, konstruiert, variiert und analysiert und die beobachteten Phänomene möglichst anschaulich begründet werden. Die vorgeschlagenen Experimente verwenden dabei diverse Materialien – von Papier und Pappe (Falten, Schneiden, Kleben) über klassische Konstruktionen mit Zirkel und Lineal bis hin zur dynamischen Geometrie-Software (DGS) GeoGebra. Entsprechende Grundkenntnisse im Umgang mit GeoGebra werden dabei vorausgesetzt. Im gesamten Buch stehen problemorientierte Ansätze, entdeckendes Lernen, Forschungsaufträge und Anwendungen im Vordergrund. In den ersten Kapiteln werden die zentralen Ziele, Inhalte und Methoden vorgestellt sowie die Inhalte der Schulgeometrie wiederholt. In den späteren Kapiteln werden diese auf einem etwas höheren mathematischen Niveau systematisiert und erweitert, jedoch nicht im Sinne einer axiomatischen Geometrie. Das Buch richtet sich vorrangig an Studierende des Lehramts der Primarstufe und Sekundarstufe I bzw. an Grund-, Haupt- und Realschulen sowie an Lehrende in diesem Bereich.

Mathematics is a subject taught from kindergarten through to high school, and yet it is the one subject that most adults are almost proud to admit to not having been very good at, and, therefore, tend to avoid it where they can. However, one of the key factors in mathematics is its ability to enable us to solve everyday problems. When we consider 'the worst-case scenario' of the situation, it is analogous to solving a mathematical problem by considering extremes. Or, we might consider the best path to take from point A to point B, where geometric relationships can be helpful. This book is intended to demonstrate a variety of neglected aspects of mathematics, in order to demonstrate the power and beauty of the field of mathematics beyond where most people, students, and teachers believe is possible.The chapters of the book explore a multitude of topics: unusual arithmetic calculations and shortcuts, entertaining and instructional problem-solving strategies, unusual applications of algebra, and how geometry allows us to better appreciate physical relationships. Only a basic mathematical knowledge is needed to understand these topics and problems; however, the book also demonstrates that, armed with even this level of understanding, our mathematical skills far exceed what we learned at school! The final chapter is the most challenging, and explores a curious problem-solving technique.

Mathematics is a subject taught from kindergarten through to high school, and yet it is the one subject that most adults are almost proud to admit to not having been very good at, and, therefore, tend to avoid it where they can. However, one of the key factors in mathematics is its ability to enable us to solve everyday problems. When we consider 'the worst-case scenario' of the situation, it is analogous to solving a mathematical problem by considering extremes. Or, we might consider the best path to take from point A to point B, where geometric relationships can be helpful. This book is intended to demonstrate a variety of neglected aspects of mathematics, in order to demonstrate the power and beauty of the field of mathematics beyond where most people, students, and teachers believe is possible.The chapters of the book explore a multitude of topics: unusual arithmetic calculations and shortcuts, entertaining and instructional problem-solving strategies, unusual applications of algebra, and how geometry allows us to better appreciate physical relationships. Only a basic mathematical knowledge is needed to understand these topics and problems; however, the book also demonstrates that, armed with even this level of understanding, our mathematical skills far exceed what we learned at school! The final chapter is the most challenging, and explores a curious problem-solving technique.

In diesem Buch soll gezeigt werden, was Funktionen in der Mathematik und in Anwendungssituationen leisten können bzw. sollen. Funktionen haben bekanntlich viele Gesichter, und das Thema ist im schulischen Mathematikunterricht und auch in den Lehramtsstudiengängen prominent vertreten. Da ist es natürlich besonders wichtig, dass Studierende einen angemessenen Zugang zu diesem Thema bekommen, sodass sie einen solchen auch an ihre zukünftigen Schüler/innen weitergeben können. Im Buch werden viele praktische und fachwissenschaftliche Aspekte angesprochen und miteinander vernetzt (z. B. zur Geometrie und zur Stochastik), die u. E. zu einem tragfähigen Gesamtbild von „Elementaren Funktionen“ führen, wobei sich an manchen Stellen auch fachdidaktische Betrachtungen finden. Dabei sollen weder Realitätsbezüge noch innermathematische Zusammenhänge und Begründungen zu kurz kommen. Dem nicht ganz leichten Ziel, Verständlichkeit und mathematische Exaktheit miteinander zu verbinden, wollenwir mit diesem Buch ein Stück näher kommen. Zahlreiche Aufgaben (teilweise mit Lösungshinweisen) runden jedes Kapitel ab und sollen Leser/innen zum Üben, Verstehen und Weiterdenken anregen.

Es gibt zahlreiche Lehrbücher zur Numerischen Mathematik, die jedoch in der Regel für die Ausbildung angehender Mathematiker/innen oder Ingenieure/innen geschrieben und auf deren spätere Berufspraxis gerichtet sind. Das vorliegende Lehrbuch widmet sich diesem auch für den Mathematikunterricht wichtigen Gebiet mit Blick auf angehende Lehrkräfte. Auf elementare Weise werden Phänomene rund um „ungenaue Zahlen“ zum Anlass genommen, die Bedeutung von Näherungswerten, Näherungsverfahren und Fehlerfortpflanzung (auf dem Niveau der Mathematik in der Sekundarstufe) deutlich zu machen. Dabei werden diese Aspekte einerseits durch den Einsatz von Computern betont, andererseits wird aber der Kulturtechnik des Überschlagsrechnens ohne Computer ein breiter Raum gegeben. So können Ergebnisse, die der Computer liefert, ohne Computer plausibilisiert werden. Zahlreiche Übungsaufgaben runden dieses Lehrbuch, das vor allem für die Aus- und Weiterbildung von SI-Lehrkräften geschrieben wurde, ab.