Question Number 133641 by mohammad17 last updated on 23/Feb/21
$${what}\:{is}\:{the}\:{mean}\:{of}\:{Ei}\left({x}\right)\:{and}\:{what}\:{is} \\ $$$${the}\:{folmulla}\:{of}\:{Ei}\left({x}\right)? \\ $$
Answered by Dwaipayan Shikari last updated on 23/Feb/21
$${Ei}\left({x}\right)=\int_{\mathrm{0}} ^{{x}} \frac{{e}^{{x}} }{{x}}{dx} \\ $$$${or}\:\int_{\mathrm{0}} ^{{x}} \frac{\mathrm{1}}{{log}\left({x}\right)}{dx} \\ $$