P.C. Mahalanobis

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             P.C. Mahalanobis   A well-known Indian statistician and scientist, Mahalanobis is greatly popular for introducing new methods of sampling. His most significant contribution in the field of statistics was the 'Mahalanobis Distance'. Besides, he had also made pioneering studies in the field of anthropometry and had founded the Indian Statistical Institute.  Originally, the family of Mahalanobis belonged to Bikrampur, Bangladesh. As a child. Mahalanobis grew up in an environment surrounded by socially active refoemers and intellectuals. He had his initial education from Brahmo Boys School Calcutta. Further, he enrolled himself into Presidency College and got a BSc degree with specialisation in physics. In 1913, Mahalanobis left for England for ther stodies and came in contact with S. Ramanujan, the famous mathematician from India. After completion of his studies. he returned

Aryabhatta

                   Aryabhatta

Aryabhatta the earliest known mathematician and astronomer of India. The birth place of Aryabhatta, who lived between circa 476-550 CE, is still a mystery. While many believe that he was born in Pataliputra in Magadha, present-day Patna in the state of Bihar, others are of the view that he was born in Kerala and lived  Magadha at the time of the Gupta rulers. His works include the Aryabhamiya (499 CE, when he was 23) and the Arya Siddhanta. 


His most famous work, Aryabhatiya is a detailed text on mathematics and astronomy. The mathematical part of the Aryabhatiya covers arithmetic, algebra and trigonometry. It also contains continued fractions, quadratic equations, sums of power series and a table of sines. Aryabhatta is believed to have written at least three texts on astronomy and wrote some free stanzas as well. Aryabhatta was a genius and all his theories continue to surprise many mathematicians of the present age. The Greeks and the Arabs developed some of his works to suit their needs.

 He wrote that if 4 is added to 100, multiplied by 8, added to 62,000 and then divided by 20,000, the answer will be equal to the circumference of a circle of diameter 20,000. This calculates to 3.1416 close to the actual value of Pi (3.14159). He was also the one who created the formula (a + b)²= a² + b ²+ 2ab.

 His other work Arya Siddhanta deals with astronomical calculation and this is evident through the writings of Aryabhatta's contemporary, Varahamihira and later mathematicians and commentators, including Brahmagupta and Bhaskara I. It contains descriptions of several astronomical instruments like gnomon (shanku yantra) ,a shadow instrument (chhaya yantra), possibly angle-measuring devices, a semicircular and circular instrument (dhanur yantra/ chakra yantra), a cylindrical stick( vasti yantra), an umbrella-shaped device called the chatra yantra and water clocks of at least two types - bow-shaped and cylindrical.


Aryabhata was aware that the earth rotates on its axis and that the earth rotates round the sun and the moon moves round the earth. He discovered the positions of the nine planets and related them to their rotation round the sun. He also knew about the eclipse of the sun, moon, about the cause of day and night, the contours of the earth and the 365 days as the exact length of the year. Aryabhata also revealed that the circumference of the earth is 39,968 km. According to modern-day scientific calculations it is 40,072 km. Solar and lunar eclipses were also scientifically explained by Aryabhata. India's first satellite, Aryabhata was named in his honour.

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