As we learn about history’s great
mathematicians, I am frequently struck by how often their pursuits are
intertwined with other disciplines. We now have concrete job titles for what a
person does—they are a mathematician, an astronomer, an engineer, a poet, a
physicist—and it is implied that one will chose a profession and stick to it. I
wonder if “mathematician” once encompassed all of these titles, and that to be
a mathematician would have implied the various applications, or if we have now
forced titles onto the work that people do, thereby corralling their ambitions
to one topic.

One individual that was heavily involved
in two disciplines—astronomy and mathematics—was Brahmagupta. It has been
estimated that Brahmagupta was born in 598 in Ujjain, India, and that he passed
in 670. During his lifetime he wrote (at least) two influential books, as well
as held the position as the head of the astronomical observatory at Ujjain,
“which was the foremost mathematical centre (sic) of ancient India at this
time.” (O’Connor and Roberts). A portion of his work has been preserved in his
book

*Brahmasphutasiddhanta*, which displayed his insights in both astronomy and mathematics. The first ten chapters of the book described astronomical phenomena. The final fifteen further explored astronomical phenomena, but it also delved into algebra and geometry (O’Connor and Roberts).
Brahmagupta uncovered great mathematical
truths in both algebra and geometry, but perhaps even more impressively, he is
attributed to defining zero as a number and negative numbers. As early as 200
A.D., a closed circle-symbol or the word “kha” would be used by those who
wanted to indicate an absence of a number or an empty place (“Zero as a Number”).
Brahmagupta defined zero as a number and dug deeper, thereby unearthing
negative numbers. In his book

*Brahmasphutasiddhanta*he outlines rules for math using zero and negative numbers, where he calls an arbitrary negative number a “debt”, an arbitrary positive number a “fortune”, and zero as zero (Mastin).
Not only did Brahmagupta provide us with
some of the building blocks of our modern number system, he concluded that
quadratic equations could have two possible solutions (and one could be
negative), he solved quadratic equations with two unknowns (which wasn’t
considered in the West for another 1000 years), and gave a formula for the area
of a cyclic quadrilateral as well as a formula for its length in relation to
its sides (Mastin; Hayashi). In exploring these concepts, Brahmagupta even
began to dabble in how we now view algebra by using the initials of the names
of colors to represent the unknowns in his equations (Mastin).

Brahmagupta’s work explored the
concretes of our solar system as well as the abstract concepts of mathematics. In
describing zero and negative numbers, Brahmagupta unequivocally changed
mathematics, and his other contributions further confirm the genius he possessed.

Works Cited

Hayashi, Takao. “Brahmagupta.”
Encyclopedia Britannica, n.d. Web. 19 Feb. 2014.Mastin, Luke. “Indian Mathemtatics-Brahmagupta.” The Story of Mathematics, n.d. Web. 19 Feb. 2014.

O’Connor, JJ, and E. F. Roberts. “Brahmagupta.”

*School of Mathematics and Statistics,*University of

St. Andrews, Scotland, n.d. Web. 19 Feb. 2014.

“Zero as a Number—Brahmagupta Period.” Wayne State University, n.d. Web. 19 Feb. 2014.

Very nice! Good overview of Brahmagupta, and your intro paragraph is a good theme that bears further exploration. 5C's: +

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