Mathematics is more than the dry textbook exercises students at various levels in India, beginning from school, are made to solve. What is missing in high school and college curricula is the excitement of mathematical research. Students, and the public, interested in mathematics, who wish to read something other than jargon-filled academic material, have nowhere to turn to. Whereas other countries have long had mathematics publications that serve the curious, the interested, and the cognoscenti, *Bhāvanā* is the first such initiative in India.

**About the word Bhāvanā**

*Bhāvanā* is a Sanskrit word that was used by ancient Indian algebraists to name a principle of “composition” introduced by Brahmagupta (born in 598 CE) in the seventh century.

In verses 64 and 65 of chapter 18 titled Kuṭṭakādhyāyaḥ of his magnum opus *Brāhma-Sphuṭa-Siddhānta* (628 CE), Brahmagupta discusses the problem of finding positive integer solutions to the equation Nx^2+1=y^2 for any arbitrary N. Brahmagupta’s composition law shows how to combine two solutions of this equation to produce a third solution. In particular, it combines two expressions of the form y_1^2-Nx_1^2 and y_2^2-Nx_2^2 to get a third expression y_3^2-Nx_3^2. The precise identity that one gets

(y_1^2-Nx_1^2)(y_2^2-Nx_2^2)=(y_1y_2+Nx_1x_2)^2-N(y_1x_2+y_2x_1)^2

is now called “Brahmagupta’s identity”.

The equation Nx^2+1=y^2 for a fixed positive integer N was later called “Pell’s equation” in modern Europe. Since Brahmagupta is arguably the first mathematician to investigate this important equation in a general framework, the equation is nowadays called the Brahmagupta–Pell equation. For more, see the article “The *bhāvanā* in Mathematics”.

Besides this mathematical usage, the word *bhāvanā* has profound nuances easily relatable in the larger Indian context, transcending linguistic barriers. In Sanskrit, its meanings include “creating”, “producing”, “generating”, “effecting”, “composing”, “accomplishing”, and “manifesting”. The word *bhāva* refers to a high spiritual state.

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We welcome your contributions to Bhāvanā, whether as a writer, reviewer, or reader with valuable feedback. Please email us at editor@bhavana.org.in.

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**Postal address :**

Bhavana Trust,

No. 24, ‘Athreya’, 21st Main, 2nd Block,

Banashankari I Stage, Bengaluru – 560050

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