Difference between revisions of "1989 USAMO Problems/Problem 3"

(New page: ==Problem== Let <math>P(z)= z^n + c_1 z^{n-1} + c_2 z^{n-2} + \cdots + c_n</math> be a polynomial in the complex variable <math>z</math>, with real coefficients <math>c_k</math>. Suppose t...)
 
(See Also)
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==See Also==
 
==See Also==
  
* [[1989 USAMO]]
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{{USAMO box|year=1989|num-b=2|num-a=4}}

Revision as of 13:24, 8 October 2007

Problem

Let $P(z)= z^n + c_1 z^{n-1} + c_2 z^{n-2} + \cdots + c_n$ be a polynomial in the complex variable $z$, with real coefficients $c_k$. Suppose that $|P(i)| < 1$. Prove that there exist real numbers $a$ and $b$ such that $P(a + bi) = 0$ and $(a^2 + b^2 + 1)^2 < 4 b^2 + 1$.

Solution

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See Also

1989 USAMO (ProblemsResources)
Preceded by
Problem 2
Followed by
Problem 4
1 2 3 4 5
All USAMO Problems and Solutions