Is it possible to write x^2 on the blackboard?(ToT2007-Fall)
Source:
September 3, 2011
calculusintegration
Problem Statement
Initially, the number and a non-integral number are written on a blackboard. In each step, we can choose two numbers on the blackboard, not necessarily different, and write their sum or their difference on the blackboard. We can also choose a non-zero number of the blackboard and write its reciprocal on the blackboard. Is it possible to write on the blackboard in a finite number of moves?