In Response To 'Re: Re: A question about formatting?'
When I evaluated your notebook I got .
I then exited without saving and opened up your notebook again. I wrapped FullForm around the odd result in your last cell and that showed me
Plus[Complex[0.75473794784929`, 0.6560263943441929`], Times[Complex[0.0041198226593061466`, 0.004273953160228585`], TextCell[""]], Times[Complex[-2.11222833230764`*^-6, -4.288587877640534`*^-6], Power[TextCell[""], 2]], Times[Complex[2.1120597302794434`*^-8, 3.6278961705986504`*^-8], Power[TextCell[""], 3]], Times[Complex[-3.5420573670914304`*^-11, -6.850831473753004`*^-11], Power[TextCell[""], 4]]]
Notice those four TextCell[""]. That seems like it is the source of the problem. But I can't track down where it is coming from.
There is some whitespace in your U[x_] definition. Maybe that is it. But anything I touch, at least on my system, seems to make it go away.
See if this provides you any clues and if you can verify that TextCell[""] on your system. I think that is the problem, we just need to figure out where it came from and how to get rid of it.