**Bhāskara-***Greatest mathematician of medieval India***.**

A 12th century Indian mathematician & astronomer who accurately defined many astronomical quantities, including the *length of the sidereal year*. As a mathematician, he made the significant discovery of the principles of *differential calculus* and its application to astronomical problems and computations *centuries before European mathematicians like Newton and Leibniz made similar discoveries*.He is credited to have given a proof of the *Pythagorean theorem by calculating the same area in two different ways and then canceling out terms to get a**^**2 + b**^**2 = c**^**2*. It is believed that Bhaskara II was the *first to conceive the differential coefficient and differential calculus.* Bhaskara II in his major work *‘Siddhanta Siromani’* (“Crown of treatises”) was completed in 1150 in which he gave mainly definitions *arithmetical terms, interest computation, arithmetical and geometrical progressions, plane geometry, and solid geometry among others and a number of methods of computing numbers such as multiplications, squares, and progression*

**2. Brahmagupta****

The man who gave the concept of

‘

A positive number multiplied by a positive number is positive.’, ‘A positive number multiplied by a negative number is negative’, ‘A negative number multiplied by a positive number is negative’ and ‘A negative number multiplied by a negative number is positive’

The book written by him also consisted of many geometrical theories like the ‘*Pythagorean Theorem’ for a right angle triangle*. Brahmagupta was the* one to give the area of a triangle and the important rules of trigonometry such as values of the sin function. He introduced the formula for cyclic quadrilaterals.* He also gave ** the value of ‘Pi’ as square root ten to be accurate and 3 as the practical value**. Additionally he introduced the concept of negative numbers. Brahmagupta argued that the Earth and the universe are round and not flat. He was the first to use mathematics to predict the positions of the planets, the timings of the lunar and solar eclipses. Though all this seems like obvious and simple solutions it was a major improvement in science at that time. He also calculated the length of the solar year which was 365 days, 5 minutes and 19 seconds which is quite accurate based on today’s calculation of 365 days, 5 hours and 19 seconds.

**3.Mahavira****

*Mahavira was 8th century Indian mathematician (Jain) from Gulbarga who asserted that the s**quare root of a negative number did not exist**. He gave the sum of a series whose terms are squares of a arithmetical progression and empirical progression and empirical rules for area and perimeter of an ellipse.Mahavira established equations for the sides and diagonals of cyclic quadrilateral.If sides of cyclic quadrilateral are a,b,c,d and its diagonals are x and y while*

**4.Varāhamihira****

*Varahamihira improved the accuracy of Aryabhatta’s sine tables. Varahamihira also defined the algebraic properties of zero and negative numbers. He was among the first mathematicians to discover a version of Pascal’s triangle as we know it today.He was aware of **gravity over a millennium before Isaac Newton**.*

Some important trigonometric results attributed to Varahamihira::

**5. Prafulla Chandra Ray: father of Indian Chemistry****

Prafulla Chandra was a synthetic chemist specially of inorganic compounds. He first became well known for his work on the inorganic and organic nitrites.He published about two hundred original papers.In 1895 Prafulla Chandra reported the first synthesis of the hitherto unknown mercurous nitrite.

The preparation of Hg2 (NO)2 was an accidental discovery. He wanted to prepare water soluble mercurous nitrate as an intermediate for the synthesis of calomel, Hg2 C12. Accordingly, dilute aqueous nitric acid (1 :4) was reacted with excess mercury. To his surprise this resulted in the formation of yellow crystalline.*One of the very notable contributions of Prafulla Chandra in the field of nitrite chemistry was the synthesis of ammonium nitrite* in pure form via double displacement between ammonium chloride and silver nitrite.Prafulla Chandra made major contributions in Coordination Compounds,Organic Sulphur compounds and developed certain methods for facile fluorination of organic compounds using thallous fluoride as the fluorinating agent.

**6. Har Gobind Khorana**Nobel Prize winner The Man who helped in Unlocking the secret of DNAs:**

He won a Nobel Prize in 1968 for his work on genes and nucleotides, which are the basic structural units of DNA.Nucleotides basically are the subunits of DNA or RNA, and consist of bases made of nitrogen. There are four types of nucleotides for each DNA, and RNA, an the order in which they are put connected and forming the double helix and is important for determining which types of proteins the cells create. Proteins are responsible for basic form and functions.

**7. Meghnad Saha****

Meghnad Saha invented an instrument to measure the* weight and pressure of solar rays*. He also gave the world the *theory of ionization which explained the origin of stellar spectra. Saha ionization equation which is related to the ionization state of an element to the temperature and pressure. This equation is used to explain the spectral classification of stars.*

**8. Subrahmanyan Chandrasekhar****

Chandrasekhar determined that a star having a mass more than 1.44 times that of the Sun does not form a white dwarf but instead continues to collapse, blows off its gaseous envelope in a supernova explosion, and becomes a Neutron star. An even more massive star continues to collapse and becomes a black hole. The calculations made by him contributed to the eventual understanding of supernovas, neutron stars, and black holes.

There are many Indian Scientist,Astrologers,Mathematicians who actually gave theories long before Europeans,who had major contributions in major field of sciences.We remember handful of names while there are many more about whom every indian should know about.

*“**It is strange that only extraordinary men make the discoveries, which later appear so easy and simple**” – Georg C. Lichtenberg*