Can someone show me how
I understand that you repeatedly integrate by parts, but how does everything reduce to ?
But in the result of each intagration by part , there is a remaining integral (to be used at the next step). Where is the last remaining integral ?
You did it 10 times. OK. But what happend before, if k=4 for example ?
And do not forget that the limits of the integral are t=0 and t=infinity. Where are they applied into your result ?