solutions to quartic and cubic equations



Dear fellow nettors,
 	             I am looking for routines, or a place (ftp site, etc) where I can
 find them, which will solve quartic and cubic equations analytically. Though the
 form of these solutions are know, problems have arisen when the coefficients
 differ by many orders of magnitude. Any help would be appreciated. I will
 summarise if enough interest is generated.
 Thank you,
 Karthik Iyer