Thank you so much, Markiyan Hirnyk. It does work perfectly now with the method specified!

Does that mean Maple failed to identify an appropriate method for integration?

After posting this message, I actually tried a different approach to request the integration. And it also worked somehow.

g:=unapply(1/z*dF(z,y)*BesselI(lambda,z),z):
evalf(Int(g,8 .. 100));

I don't know understand why putting it this way makes Maple work perfectly but not the original way. Anyway, I am so happy it works now. Thank you so much for your help!!!!!!!

Thank you so much, Markiyan Hirnyk. It does work perfectly now with the method specified!

Does that mean Maple failed to identify an appropriate method for integration?

After posting this message, I actually tried a different approach to request the integration. And it also worked somehow.

g:=unapply(1/z*dF(z,y)*BesselI(lambda,z),z):
evalf(Int(g,8 .. 100));

I don't know understand why putting it this way makes Maple work perfectly but not the original way. Anyway, I am so happy it works now. Thank you so much for your help!!!!!!!

Sorry I forgot to copy the value assigned to lambda. This should be included in the previous set of commands.

lambda:=6.248711867.