quality:corruption
Exponential and logarithmic behavior: bracketing

From the two series suggested in previous subsections, it follows that E 1 {\displaystyle E_{1}} behaves like a negative exponential for large values of the argument and like a logarithm for small values. For positive real values of the argument, E 1 {\displaystyle E_{1}} can be bracketed by elementary functions as follows:

The left-hand side of this inequality is shown in the graph to the left in blue; the central part E 1 (x) {\displaystyle E_{1}(x)} is shown in black and the right-hand side is shown in red.