Hi everybody,

I have a function:

,

and I would like to integrate it twice against x to obtain .

More precisely, I need to compute

,

which can also be written

.

However there are no symmetries that can be exploited. can have any positive real value.

Until now I have obtained a quite complicated expression for with explicit terms and two simple integrals which I can't figure out how to compute, namely :

,

and

.

Any idea to integrate this function ? I have not been lucky with variable changes...

Thanks,

Kind regards,

Arixo

PS: for those interested, it is an integration involved in the computation of the van der Waals interaction energy between two solid cubes of size a1 and a2 and separated by a distance d in the x direction...