thanks M28 , your reply was helpful as it does form part of a solution
as far as mathcad is concerned .there does seem to be more to it which i do
not understand yet , involving Ei , the exponential integral .I wonder if captain black can explain this ?
or the offset logarithmic integral (to aviod the singularity at 1):
But also the exponential integral:
Now this has not been as careful as I would like so still probably needs checking some more.
See the Wikipedia artice on the logarithmic integral for more information.
I would like to show symbols . As i am very newbie , i'm in need of tutorials so as to better illustrate my questions .
I came across the integral when reading about Guass . It looked harmless untill i tried to integrate . Eventually i gave up and solved it symbolic using mathcad .Then i realised i was in over my head with the Ei.
My next quest is to understand how Ei is derived .
many thanks .