Difference between revisions of "2013 UMO Problems/Problem 5"

(Created page with "== Problem == Cooper and Malone take turns replacing <math>a</math>, <math>b</math>, and <math>c</math> in the equation below with real numbers. <cmath>P(x) = x^3 + ax^2 + bx + ...")
 
m (Problem)
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Cooper and Malone take turns replacing <math>a</math>, <math>b</math>, and <math>c</math> in the equation below with real numbers.
 
Cooper and Malone take turns replacing <math>a</math>, <math>b</math>, and <math>c</math> in the equation below with real numbers.
<cmath>P(x) = x^3 + ax^2 + bx + c</cmath> . Once a coefficient has been replaced, no one can choose to  
+
<cmath>P(x) = x^3 + ax^2 + bx + c.</cmath> Once a coefficient has been replaced, no one can choose to  
 
change that coefficient on their turn. The game ends when all three coefficients have been chosen.  
 
change that coefficient on their turn. The game ends when all three coefficients have been chosen.  
 
Malone wins if <math>P(x)</math> has a non-real root and Cooper wins otherwise. If Malone goes first, find the person who has a winning strategy and describe it with proof.
 
Malone wins if <math>P(x)</math> has a non-real root and Cooper wins otherwise. If Malone goes first, find the person who has a winning strategy and describe it with proof.
 
  
 
== Solution ==
 
== Solution ==

Revision as of 03:39, 14 October 2014

Problem

Cooper and Malone take turns replacing $a$, $b$, and $c$ in the equation below with real numbers. \[P(x) = x^3 + ax^2 + bx + c.\] Once a coefficient has been replaced, no one can choose to change that coefficient on their turn. The game ends when all three coefficients have been chosen. Malone wins if $P(x)$ has a non-real root and Cooper wins otherwise. If Malone goes first, find the person who has a winning strategy and describe it with proof.

Solution

See Also

2013 UMO (ProblemsAnswer KeyResources)
Preceded by
Problem 4
Followed by
Problem 6
1 2 3 4 5 6
All UMO Problems and Solutions