Math for everyone
Mathematical content accessible to everyone

The king of geometry: Thales' theorem
In France, Thales' theorem concerns parallel lines and proportionality. Its proof, combining algebra and plane geometry, is remarkably elegant. It also leads naturally to two landmark results in triangle geometry: Menelaus' and Ceva's theorems.

Beware of statistics
A news brief in Challenges 429 (April 2015) reports that "48% of American women aged 15 to 44 have no children."

The Simpsons: a website and books — maths in series | Tangente
Countless series have taken an interest in science over the past dozen years or so. Mostly crime dramas, they draw on elements from biology, and sometimes from mathematics, as with Numb3rs.

The subverted geometry of Julien Prévieux | Tangente
The exhibition by Julien Prévieux, winner of the 2014 Marcel Duchamp Prize, "Des corps schématiques", running until 1 February 2016 at the Centre Pompidou (Paris), is not, strictly speaking, mathematical art, but since its theme is the recording of movement, some of the artist's geometric obsessions inevitably appear.

Arithmetic on stage: when numbers invade the stage | Tangente
Reality, by Daria Deflorian and Antonio Tagliarini, was performed this past autumn at the Théâtre de la Colline in Paris (20th arrondissement), and what interests us here is not so much the play's characters as the relationship between its heroine, Janina Turek, and numbers.

Music, serenity, and fractal art: a meeting | Tangente
The artist Alan Stivell, a musician, lyricist, composer and performer well known to defenders of Breton culture, chose a fractal image to illustrate his twenty-fourth album, AMzer (World Village, 2015).

Girls' mathematics competitions: EGMO and more | Tangente
There have always been girls' athletics and skiing competitions, and girls' chess competitions have existed since 1927... So why not consider mathematics competitions for girls? Let's take stock of the existing initiatives.

Did you say "Extraordinary"? Magic square and memory | Tangente
When film puts mathematics in the spotlight, it is often to link it with autism, as in the recent film Le Monde de Nathan (see Tangente 165). When television puts it in the spotlight, it is to showcase feats.

Dynamic geometry: plane motion | Tangente
Plane motion provides a valuable framework for using kinematics to study the geometric properties of figures. In particular, it offers an efficient and insightful way to determine loci. In the past, it was studied in connection with the connecting-rod and crank mechanisms of locomotives.

Adventurers of the forgotten pentagon: tiling the plane | Tangente
The recent discovery of a pentagon that tiles the plane brings to mind an endearing figure: Marjorie Rice. An American homemaker, she would hide away in her kitchen to indulge her passion for mathematics.

Thales and his theorem: historical uncertainty explained | Tangente
Who has never heard of Thales's theorem? Yet this extremely famous geometric statement is also one of the theorems whose history is least certain. Let's try to separate history from legend...

Fashion by algorithm: predicting trends with math | Tangente
Who are these devils dressed in Prada in New York? It's not a joke — it's the title of a scientific paper by researchers from the eminently respectable National Taiwan University and University of Rochester (United States).

The ubiquitous normal distribution
Is it not astonishing that chance should obey a law? Two of the greatest mathematical geniuses proved that most random phenomena are governed by the "normal" distribution. Simple in form, it underpins the statistical interpretation of a set of measurements.

The choice of serve in tennis
A probabilistic model can help a tennis player choose which type of serve to use. Applied to the final of the last Davis Cup, which pitted Belgium against England.

Yesterday's conjectures, today's progress | Tangente
Egyptian fractions, like Einstein's relativity, provide the subject matter for conjectures that have only just been proved. The strange abc conjecture, simple to state, has just been resolved... if the proof put forward by Mochizuki turns out to be correct.

Maths and sport: probability and news | Tangente
The relationship between mathematics and sport is not purely theoretical. It is used every day by athletes, by those who coach them, and by the developers who simulate them.

Mathematical Art: Geometry and Creation | Tangente
Art and geometry always go well together; the material doesn't matter — wood, brick or even chocolate — as long as the shape is beautiful.

Goal average and rankings: sporting fairness | Tangente
Breaking ties, showcasing the spectacle of sport: that is the role of the points system, often modified over time. But does this move toward greater fairness? And how can cheating be avoided?

Tao solves Erdős's discrepancy conjecture | Tangente
Terence Tao is one of the great "problem posers" of his time, since a photograph that went around the world shows him, at ten years old, already at work with the famous Hungarian mathematician.

2016, a rich vintage
The entire Tangente editorial team joins in wishing its readers a very happy 2016. The gift it has cooked up for you? A bouquet of properties of the number 2016!
