Real game with a computer
Source: Indonesian National Science Olympiad 2018, Mathematics P4
July 6, 2018
algebra
Problem Statement
In a game, Andi and a computer take turns. At the beginning, the computer shows a polynomial where , such that it doesn't have real roots. Andi then begins the game. On his turn, Andi may change a polynomial in the form into either or . However, Andi may only choose a polynomial that has real roots. On the computer's turn, it simply switches the coefficient of and the constant of the polynomial. Andi loses if he can't continue to play. Find all such that Andi always loses (in finitely many turns).