Plotting the Exponential Integral

[doviedo2 (Diego M. Oviedo-Salcedo)]

Hello,

I have used the buit-in symbol ExpIntegralEi and no problem, but when I used the following, I am getting an error message. Does anyone know how to solve this issue?

LogLogPlot[ NIntegrate[Exp[-i]/(i), {i, 1/u, [Infinity]}], {u, 0.1, 10000}]

[fkampas (Frank Kampas)]

I think the parenthesis around i and the wrong expression for infinity are the problems.
When troubleshooting, it’s best to break things up into smaller parts.

f[u_] := NIntegrate[Exp[-i]/i, {i, 1/u, \[Infinity]}]

LogLogPlot[f[u], {u, .1, 10000}]