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Brahmagupta

  • Writer: toinfinityandbeyondmathclub
    toinfinityandbeyondmathclub
  • Apr 8, 2022
  • 2 min read

Updated: May 18, 2023

Brahmagupta, the son of astrologer Jishnugupta, was born in 597 AD and lived till 668 AD. Born in the city of Bhinmal, Brahmagupta was also an astrologer like his father. He later became the director of Ujjain, which was the centre of Ancient Indian Mathematical Astronomy. However, today he is widely regarded as one of the greatest mathematicians, rather than an astronomer, because of his significant contributions in the field of mathematics.


All the contributions and findings of Brahmagupta are written in the form of poetry. This style of writing was a commonly used practice in Indian mathematics. His main work, known as Brahmasphutasiddhanta, is very popular as it contains important content related to the role of the number zero, rules of manipulating positive and negative numbers, and multiple ways of solving linear and quadratic equations.


THE DISCOVERY OF ZERO


The Babylonians considered the number zero as a symbol to show the lack of a certain quantity; however, it was Brahmagupta who stated that zero is a separate number in itself. He established the basic concept of dealing with zero: 1 + 0 = 1 , 1 - 0 =1, and 1 x 0 = 0 .


POSITIVE AND NEGATIVE NUMBERS


Previously, the sum of 3 – 4 was considered to be zero or meaningless, but it was Brahmagupta who realized that there can be negative numbers. He referred to them as ‘debt’. This was owing to the number’s negative property. On the contrary, he called positive numbers ‘fortune’. Based on this, he discovered a new set of rules whose usage can be seen in day-to-day life in today’s mathematics.


His findings were:


  • A debt minus zero is a debt.

  • A fortune minus zero is a fortune.

  • Zero minus zero is a zero.

  • A debt subtracted from zero is a fortune.

  • A fortune subtracted from zero is a debt.

  • The product of zero multiplied by a debt or fortune is zero.

  • The product of zero multiplied by zero is zero.

  • The product or quotient of two fortunes is one fortune.

  • The product or quotient of two debts is one fortune.

  • The product or quotient of a debt and a fortune is a debt.

  • The product or quotient of a fortune and a debt is a debt.





QUADRATIC EQUATIONS


The general solution for the commonly used quadratic equations was founded by Brahmagupta. He not only solved quadratic equations that included irrational numbers but also figured that quadratics equations have two solutions or roots.


BRAHMAGUPTA’S FORMULA


He found the expression: under root (s-a)(s-b)(s-d) to find the area of a quadrilateral.


Some of his other discoveries include finding the values of the sine function, the value of pi as square root, and calculating cube and square roots using complex working which would be extremely difficult to explain in this article comprehensively!


- Varada Rohokale




BIBLIOGRAPHY











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