Query: unknown quantities

[Elliot Stern]

My twelve year old son brought home a math assignment on Friday that
involves "ancient Hindu" mathematics. I have not been able to help him, as
my knowledge of this field is limited, as are the resources available at
home.

The question is: What notation did ancient Greek and ancient Hindu
mathematicians use for unknown quantities? I have taken this to refer to
such unknown quantities as we might indicate by x, y, and z, or other
letters in such expressions as 2x = 4.

The Encyclopedia Britannica article "History of Mathematics" mentions
Diophantus of Alexandria (lived some time between 2nd century BC and 3rd
century AD) as having used a figure resembling the Roman letter S as the
unknown quantity, but does not mention if Indian mathematicians used any
such figures. Secondary sources at home that treat Indian mathematics in
any way do not treat this matter. Rapid and superficial perusal of the few
Sanskrit mathematical texts I have suggests to me that there may be no
figurative or symbolic notation, but I would welcome any informed answer,
so that I can help my son answer his question.

Thank you in advance.


Elliot M. Stern
552 South 48th Street
Philadelphia, PA 19143-2029
USA

telephone: 215 747 6204