Irrationals in Ancient India

摘要

We discuss the question: In which century were irrational numbers known to Indians? This study becomes a bit complicated when we distinguish the knowledge of irrationality of a number from the knowledge of an irrational number. The irrational numbers like π and √2 were known about three millennia ago, closer and closer rational approximations to them were also attempted long ago, but it is doubted whether the concept of irrationality was known to those who made these attempts.