A Note on Computing Approximations to the Exponential Function
Two methods are discussed which result in near
minimax rational approximations to the exponential 
function and at the same time retain the desirable property
that the approximation for negative values 
of the argument is the reciprocal of the approximation
for corresponding positive values.  These methods 
lead to approximations which are much superior to the
commonly used convergents of the Gaussian continued 
fraction for the exponential.  Coefficients and errors
are given for the intervals [-.5*ln 2, .5*ln 2] 
and [-ln 2, ln 2].
CACM January, 1967
Cody, W. J.
Ralston, A.
