- #1
EngWiPy
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After following the logical steps to derive something, I reached to the following integral:
[tex]\int_0^{\infty}\frac{1}{x^2}\exp\left(\frac{A}{x}-x\right)E_1\left(B+\frac{A}{x}\right)\,dx[/tex]
where ##E_1(.)## is the exponential integral function, and ##A## and ##B## are non-zero positive constants. I tried to find this integral in the table of integrals, but couldn't find it. Next best thing to do is to evaluate this integral numerically, I guess. So, I resorted to Mathematica for that purpose, and used the Nintegrate command, but I got a message that the integrand has evaluated to overflow, indeterminate, or infinity. It suggested to increase the number of recursive refinements, but it didn't work. Is there something fundamentally wrong in the integral, or it's just a technical issue, and how to overcome it? I have to mention that when I replaced the lower bound of the integral by a very small value that is greater than 0, the integral was calculated perfectly. Is this the problem maybe?
Thanks
[tex]\int_0^{\infty}\frac{1}{x^2}\exp\left(\frac{A}{x}-x\right)E_1\left(B+\frac{A}{x}\right)\,dx[/tex]
where ##E_1(.)## is the exponential integral function, and ##A## and ##B## are non-zero positive constants. I tried to find this integral in the table of integrals, but couldn't find it. Next best thing to do is to evaluate this integral numerically, I guess. So, I resorted to Mathematica for that purpose, and used the Nintegrate command, but I got a message that the integrand has evaluated to overflow, indeterminate, or infinity. It suggested to increase the number of recursive refinements, but it didn't work. Is there something fundamentally wrong in the integral, or it's just a technical issue, and how to overcome it? I have to mention that when I replaced the lower bound of the integral by a very small value that is greater than 0, the integral was calculated perfectly. Is this the problem maybe?
Thanks