David Mumford, the eminent mathematician writes in his review of the book, Mathematics in India by Kim Plofker:
"Did you know that Vedic priests were using the so-called Pythagorean theorem to construct their fire altars in 800 BCE?; that the differential equation for the sine function, infinite difference form, was described by Indian mathematician-astronomers in the fifth century CE?; and that 'Gregory's' series PI/4 = 1 -1/3+1/3-… was proven using the power series for arctangent and, with ingenious summation methods, used to accurately compute PI in southwest India in the fourteenth century?
(source: Mathematics in India - Reviewed by David Mumford - AMS American Mathematical Society - Volume 57 Number 3).
"Did you know that Vedic priests were using the so-called Pythagorean theorem to construct their fire altars in 800 BCE?; that the differential equation for the sine function, infinite difference form, was described by Indian mathematician-astronomers in the fifth century CE?; and that 'Gregory's' series PI/4 = 1 -1/3+1/3-… was proven using the power series for arctangent and, with ingenious summation methods, used to accurately compute PI in southwest India in the fourteenth century?
(source: Mathematics in India - Reviewed by David Mumford - AMS American Mathematical Society - Volume 57 Number 3).