Difference between revisions of "1983 USAMO"

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==Problem 1==
 
==Problem 1==
 
  If six points are chosen sequentially at random on the circumference of a circle, what is the probability that the triangle formed by the first three is disjoint from that formed by the second three?
 
  If six points are chosen sequentially at random on the circumference of a circle, what is the probability that the triangle formed by the first three is disjoint from that formed by the second three?
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==Problem 2==
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Prove that the zeros of
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<cmath>x^5+ax^4+bx^3+cx^2+dx+e=0</cmath>
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cannot all be real if <math>2a^2<5b</math>.

Revision as of 19:02, 13 November 2011

Problem 1

If six points are chosen sequentially at random on the circumference of a circle, what is the probability that the triangle formed by the first three is disjoint from that formed by the second three?

Problem 2

Prove that the zeros of

\[x^5+ax^4+bx^3+cx^2+dx+e=0\]

cannot all be real if $2a^2<5b$.