# Evklid

Nationality: Greece

**Background**

Some biographical data are preserved in the pages of the Arabic manuscripts of the XII century: "Euclid Naukrata son, known as" geometry ", a scientist of the old time, in origin a Greek residence on a Syrian, a native of Tyre."

King Ptolemy I in Egypt attracted scholars and poets, creating for them the temple of the Muses - Museyon. Among the invited scientists and proved Euclid, who founded in Alexandria - Egypt`s capital - mathematical school and wrote his fundamental work for her students, united under the common name "Start". It was written about 325 BC.

"Beginnings" are composed of thirteen books, built on a single logic. Each of the thirteen books begins the definition of concepts (point, line, plane, figure and so on. D.), Which are used in it, and then on the basis of a small number of basic provisions (5 axioms and 5 postulates) accepted without proof, the whole system is built geometry.

Books I-IV encompass geometry, the content goes back to the works of the Pythagorean school. In Book V developed the doctrine of proportions. In VII-IX books contained the study of numbers, representing the development of the Pythagorean Sourcebook. In X-XII books contain the definition of areas in the plane and in space (Geometry), irrationality theory (especially in the tenth book); in the XIII book contains studies of regular solids.

"Beginnings" of Euclid is a summary of the geometry, which is known to this day called Euclidean geometry. It describes the metric properties of space that modern science calls the Euclidean space. This space is empty, infinite, isotropic, having three dimensions. Euclid gave a mathematical certainty atomistic idea of ??empty space, in which the geometric object moves atomy.Prosteyshim Euclid is the point, which he defines as that which has no parts. In other words, the point - it is indivisible atom of space.

The doctrine of the parallel lines and the famous fifth postulate ( "If a straight line falling on two straight lines makes the interior and on one side of the angles less than two right, the continuation of unbounded these two lines meet on the other side, where the angles less than two right angles") determine the properties of Euclidean space and its geometry, different from the non-Euclidean geometry.

For four centuries, the "Start" published 2500 times: 6-7 year editions came out in the middle. Until the XX century book was considered a major textbook on geometry, not only for schools but also for universities.

Euclid belong partially preserved, partially reconstructed in further mathematical works. It was he who introduced the algorithm for polucheniyanaibolshego common divisor of two natural numbers randomly selected and the algorithm named "account of Eratosthenes" - for finding prime numbers from this number.

Euclid has laid the foundation of geometrical optics, set them in the writings of "Optics" and "Catoptrics". In Euclid, we also meet the description of the monochord - odnostrunnogo instrument to determine the height of the string tone and its parts. The invention monochord has been important for the development of music. Gradually, instead of one, two or three strings were used. Thus began the creation of keyboard instruments, the harpsichord, first, and then the piano.

Of course, all the features of Euclidean space were opened immediately, but as a result of centuries of work of scientific thought, but the starting point of this work were the "beginning" of Euclid. Basic knowledge of Euclidean geometry is now an essential element of general education in the world.