Madhava of Sangamagrama is widely regarded as the father of Indian calculus due to his significant contributions to the development of calculus in the 14th century.

Madhava of Sangamagrama developed the Madhava series, which is an infinite series expansion that approximates the value of a function at a given point.

Bhaskara II introduced the concept of fluxions, which is similar to the modern concept of derivatives, in the 12th century.

Bhaskara II discussed the concept of fluxions in his treatise Siddhanta Shiromani, which is a comprehensive work on astronomy and mathematics.

Srinivasa Ramanujan developed the Ramanujan's modular theorem, which provides a relationship between the derivatives of modular forms.

S. Ramanujan made significant contributions to the theory of elliptic functions, which are a class of special functions that arise in various areas of mathematics and physics.

Srinivasa Ramanujan and G.H. Hardy founded the Ramanujan Journal, which is a peer-reviewed academic journal dedicated to publishing research in all areas of mathematics.

S.L. Loney made significant contributions to the development of fractional calculus, which is a branch of mathematics that deals with derivatives and integrals of arbitrary order.

S.L. Loney wrote the book "An Elementary Treatise on the Differential Calculus", which is a comprehensive textbook on differential calculus.

N.C. Gupta is known for his contributions to the teaching of calculus in schools and colleges. He wrote several textbooks on calculus that are widely used by students and educators.

N.C. Gupta wrote the book "A Textbook of Calculus", which is a comprehensive textbook on calculus that covers both differential and integral calculus.

B.C. Das made significant contributions to the study of the mean value theorem, which is a fundamental theorem in calculus that relates the average value of a function on an interval to the value of the function at a point in the interval.

B.C. Das developed Das's mean value theorem, which is a generalization of the mean value theorem that applies to functions of several variables.

P.K. Jain is known for his contributions to the teaching of calculus through his textbooks. He wrote several textbooks on calculus that are widely used by students and educators.

P.K. Jain wrote the book "Calculus and Its Applications", which is a comprehensive textbook on calculus that covers both differential and integral calculus, along with applications in various fields.