[math-fun] Indian series for pi

I came across a Math History web site. The authors take seriously the Indian claims of inventing the Gregory series for arctangent, and the power series for sin and cos, circa 1400. http://www-history.mcs.st-andrews.ac.uk/history/Mathematicians/Madhava.html Madhava's math works are lost, but are described in Nilakantha's writings, including proofs of the series. I suppose the whole thing could be a hoax, but it's a pretty long running one, involving several people. Assuming it's all true, we must ask "What happened to Indian Calculus?" How did it disappear? Why has it only come to Western attention recently? Rich rcs@cs.arizona.edu