Exponential Integral Ei x actual ei(x) 0.10 -1.622810 -1.622813 0.20 -0.821761 -0.821761 0.30 -0.302669 -0.302668 0.40 0.104768 0.104765 0.50 0.454220 0.454220 0.60 0.769881 0.769881 0.70 1.064910 1.064907 0.80 1.347400 1.347397 0.90 1.622810 1.622812 2.20 5.732610 5.732615 2.40 6.600670 6.600670 3.50 13.925400 13.925355 3.90 18.315701 18.315716 5.00 40.185299 40.185280 5.40 54.193501 54.193474 12.50 23565.099609 23565.121094 13.00 37197.699219 37197.675781 13.50 58827.000000 58826.957031 14.00 93193.000000 93192.515625 14.50 147866.000000 147866.156250 15.00 234955.000000 234955.890625