where y belongs to the interval (x, x+1).
From the above computation,I think, it should be bounded by a constant C, not Ce^{-x}. are you sure it is Ce^{-x}? I guess This boundry is too strong .
It does say that in Rudin, if you have it chapter 6 problem 14. But what you did helped. I went about proving the the <2 part a bit incorrectly. Thank you for your help though.