Thales

Thales is a Greek mathematician, astronomer and philosopher. He was born in 654 BC in Miletus (Greece) and he died in 546 BC. A lot of people regard him as the first philosopher because he tried to explain natural phenomena without referencing to mythology and gods. For example he tried to explain earthquakes by saying that the earth floats on water and each time an earthquake occur it is due to the movement of the waves.

Major work:-He determined the day of a solar eclipse.
-He calculated the height of the pyramids by calculating the height of its shadow at the same time his height measured the same height as his shadow.
-There are two Thales’ theorems:-If a, b and are points on a circle and AC is the diameter of the circle the angle ABC is a right angle:

α+ (α+β) + β = 180°

2α + 2β = 180°

α + β= 90°

-(DE) //(BC)

ERASTOSTHENES

He was an astronomer, geographer, philosopher and mathematician Greek. He was born in 276 B.C in Libya and died in 194 B.C in Egypt. He was student of Ariston of Chios. Erastosthenes was appointed head of library in 245 B.C at the request of Ptolemy 3 , pharaoh of Egypt , and was tutor to his son Ptolemy4 . The asteroid 3251 was named Erastosthenes in his honor. As a matematician, he established the sieve of Erastosthenes , a method to find by excluding , all the prime numbers. He worked on the problem of duplication of the cube and imagined the mesolable, instrument to know the average proportion.

As an astronomer , he showed the inclination of the ecliptic on the equator and he invented the armillary sphere. His studies focused on the distribution of oceans and continents, the winds , areas climate , and elevations of mountains. He attributes the term geography. He left a general map of the ecumene which was for a long time the unique base of geography. It's the study of the circumference ( or meridian )of the Earth that marks the most work of Erastosthenes. He deduced the circumference in a purely geometrical way.

Minagaetry

Jerome Cardan: A French mathematician !!!!!

Jerome Cardan was born on the 24^th of September 1501 and died on the 21^st 1576. He was a celebrated Renaissance mathematician, physician, astrologer, and gambler.

He was born in Pavia, Italy; He is the child of a mathematically gifted lawyer who was a friend of Leonardo da Vinci. In 1520, he entered the University of Pavia and later in Padua he studied medicine. His eccentric and confrontational style did not earn him many friends and he had a difficult time finding work after his studies had ended.

Eventually, he managed to develop a considerable reputation as physician and his services were highly valued at the courts. He was the first to describe typhoid fever.

Today, he is best known for his achievements in algebra. He published the solutions to the cubic

And quartic equations in his 1545 book Ars magna. Part of the solution to the cubic was communicated to him by Niccolo Fontana Tartaglia, and the quartic was solved by Cardan’s student Lodovico Ferrari. Both were acknowledged in the foreword of the book.

Cardan invented several mechanical devices including the combination lock, the gimbal consisting of three concentric rings allowing a supported compass or gyroscope to rotate freely, and the Cardan shaft with universal joints, which allows to transmit rotary motion at various angles and is used in vehicles to this day.

Cardan was accused of heresy in 1570 because he had computed and published the horoscope of Jesus in 1554. He was arrested and had to spend several months in prison, was forced to abjure and give up his professorship. He moved to Rome, received a lifetime annuity from Pope Gregory XIII and finished his autobiography. He died there on the day he had (supposedly) astrologically predicted earlier.

Pythagoras

Pythagoras is an philosopher, mathematician & scientist, he was born in 570 BC at Samos in Greek.

His father Mnesarchus was a gem-engraver and his mother was Parthénis.

Pythagoras was an Athlete in the age of 17, at the age of 18 he leaves Samos and went to Lesbos.

In 547 BC he went to Egypt to learn geometries, astronomies by Egyptians. He was the 1^st who invite a theorem to calculate the hypotenuse or other sides of a triangle.

So his theorem says that only in a right angled triangle the square of the hypotenuse is equal to the sum of the squares of the other two sides.

(a² + b² = c²).

After that he returned to Greek and opened a school, he teaches geometries…

Around 530 BC, he moved to crouton, a Greek colony in southern Italy, and there set up a religious sect.

His followers pursued the religious rites and practices developed by Pythagoras, and studied his philosophical theories.

The society took an active role in the politics of Crouton, but this eventually led to their downfall.

The Pythagorean meeting-places were burned, and Pythagoras was forced to flee the city.

He died in 495 BC at Metapontum at the age of 83, Finally his theorem was published by his students and named “Pythagorean theorem”

FRANCISCUS VIETA

FRANCISCUS VIETA

His life

Vieta was born in 1540 at Fontenay-le-Comte, Vendée and was dead on 23 December 1603 at Paris. His father was an attorney and her mother was the first president of the Catholic League of France. Vieta went to a Franciscan school and in 1558 studied law at Poitiers, graduating as a Bachelor of Law in 1559. A year later, he began his career as an attorney in his native town. He served Henry III and Henry IV. He was influenced by Ramus. As we know he was a great French mathematician whose work on new algebra was an important step towards modern algebra, due to its innovative use of letters as parameters in equations to denote quantities. Vieta was accused of Protestantism by the Catholic League, nevertheless Vieta defended and protected Protestants his whole life.

His works

1571, he discovered the first infinite product in history of mathematics by giving an expression of π:

He provides 10 decimal places of π by applying the Archimedes method to a polygon with 6 × 2¹⁶ = 393 216 sides.

Trigonometric formulas: Sin (a) +Sin (b) =Sin (a+b)* Cos (a-b)/2 where a and b are the opposite angles.

From 1571, he published Francisci Vietœi universalium inspectionum ad canonem mathematicum liber singularis; a book of trigonometry, in abbreviated Canonen mathematicum, where there are many formulas. His formulas can be proven by expanding the equality.

Vieta is considered as the most important mathematician in bridging the gap between the reconnaissance math to the modern world math.