úÎ{× estimates erfc(x) valid for 8 < x < 100 + This is based on index 5725 in Hart et al   "Error function related functions. The derivative of  is  x -> 2 / sqrt pi * exp (x^2),  and this uniquely determines  by  erf 0 = 0. Minimal complete definition is  or .  erfc x = 1 - erf x erfcx x = exp (x*x) * erfc x normcdf x = erfc(-x  sqrt 2)  2     erf-native-1.0.0.1Data.Number.ErfGSL.SpecFunc.ErfErferferfcerfcxnormcdferfferfcf erfserieserfc8 erfc8_sum