Everyday Math
Applied mathematics to everyday life: elections, sport, music, road traffic, weather, computer science, finance
Court and maths: an unprecedented ruling | Tangente
Readers of Tangente 189 (page 5) will no doubt remember Valentin Desgranges, the 19-year-old from Toulouse who submitted a sensible mathematical answer to an online competition run by a major retail chain (Auchan).
Simulated annealing
During an approximate computation, how can we distinguish a local minimum from a global one? Simulated annealing, based on a common practice in metallurgy, offers a subtle yet effective heuristic method for many applications.
Optimizing welfare?
Is the welfare of a population simply the sum of its members' satisfaction scores? This is far from certain, especially since measuring, comparing and aggregating individual utilities is no straightforward matter. Italian economist Vilfredo Pareto proposed a novel approach.
Thrifty bees
Optimize, optimize! That seems to be the bees' motto when they build their honeycombs. Let's take a closer look at their thrifty "methods." Geometry will prove invaluable in calculating the areas and angles of the cells.
Linear programming
Linear programming deals with problems that seem elementary in formulation: optimizing linear functions over a set defined by linear inequalities. Yet this theory has many highly practical applications.
The Monte Carlo method
In practice, finding an optimal value often involves computing demanding integrals. How can this be done? Physicists developed the Monte Carlo method, whose complexity does not increase with the dimension of the integrals involved.
Reuleaux: a triangle that rolls – Curves | Tangente
A circular roller may always seem ideal for moving an object. Yet this is not so: a kind of equilateral triangle with rounded sides is actually better suited to certain everyday situations.
Dendrochronology
How was a harbor built in Roman times? When was this violin made? When was a mine's infrastructure built? Dendrochronologists seek to answer all these questions by precisely dating objects, structures, or remains containing wood.
10-adic numbers
Some mathematicians, tired of manipulating objects according to established procedures, begin to play with the rules themselves. What seems to be nothing more than pure intellectual pleasure often finds unexpected applications. Such is the case with 10-adic numbers...
A free ticket to the stars: Newton | Tangente
How far we have come since Newton's famous apple! Recently discovered remarkable properties of the gravitational field raise the prospect of space missions requiring almost no energy—not only to the Moon, but to other planets as well…
Statistics and epidemiology: clusters | Tangente
An article in Science et pseudo-sciences explains the statistical methods used in epidemiological studies, using cases of "babies born without arms" as an example
Arithmetic: Were things really better before? | Tangente
The latest report from the Directorate of Evaluation, Forecasting and Performance warns of declining achievement among pupils at the end of CM2.
The astrolabe: answers to six practical challenges | Tangente
After reading the article on the planispheric astrolabe, practise using it by answering these questions
The conquering virus
Studying how viruses act also involves… geometry. In particular, determining the area conquered by a virus helps assess how dangerous it is. So let us grab a microscope! Off to the laboratory for some hands-on work…
The smooth fractal revolution
How can a sphere be made to occupy less volume? Or how can an object be brought from the fourth dimension into the third? The corrugation technique meets such geometric constraints and produces surfaces both strange and unprecedented: "smooth fractals."
The geoid: the Earth's true shape | Tangente
The surface most familiar to us, the one we walk on every day, raises its fair share of questions: what exactly is the shape of the Earth? It is neither quite a sphere nor an ellipsoid. This irregular object, the geoid, has some subtle properties. We spoke with a specialist.
Football pitch as a unit of area | Tangente
In recent years, a new unit for measuring area has emerged. Let's see how to convert between units.
The art of making numbers talk
We are awash in numerical and statistical information. Yet even objective, accurate data can be interpreted misleadingly. A little calculation and a sound grasp of error theory can correct some unwarranted conclusions.
Math-o-LU workshops launch in 2019 | Tangente
The Maison des mathématiques de l'Ouest, which brings together mathematics outreach initiatives across Pays de la Loire, and the Résonnance association, which runs dance and theater workshops linked to science, spearheaded a project to establish a mathematics club at Le Lieu Unique, a performing arts venue in Nantes (Loire-Atlantique).
The planispheric astrolabe
The astrolabe is the scientific instrument par excellence! The king of measuring instruments, it ruled supreme for more than a thousand years. It has since lost its former glory, and few people still use it or handle it with nostalgia. Yet it offers a wonderful opportunity to put mathematics into practice.