Professor D of some univeristy of Somewhere
Source: Balkan MO ShortList 2008 C1
April 5, 2020
Problem Statement
All offices of University of Somewhere are numbered with numbers for some . One day, Professor came up with a polynomial with real coefficients and power . Then, on the door of every office he wrote the value of that polynomial evaluated in the number assigned to that office. On the th office, for he wrote and on the th office he wrote .[*] Prove that Professor D made a calculation error
[*] Assuming that Professor D made a calculation error, what is the smallest number of errors he made? Prove that in this case the errors are uniquely determined, find them and correct them.