T. Sasagawa, AN INFINITE PRODUCT ARISING FROM AN ELEMENTARY GEOMETRIC PROBLEM AND THE ESTIMATE OF ITS VALUE, Applied mathematics and computation, 73(2-3), 1995, pp. 271-279
An infinite product arising from a geometric problem similar to Vieta'
s formula is considered. The value of it is estimated by using some el
ementary inequalities. The exact value seems to still be unknown. More
general infinite products of a similar type are also investigated.