Difference between revisions of "2021 AIME I Problems/Problem 15"

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==Problem==
 
==Problem==
These problems will not be available until the 2021 AIME I is released on Wednesday, March 10, 2021.
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Let <math>S</math> be the set of positive integers <math>k</math> such that the two parabolas<cmath>y=x^2-k~~\text{and}~~x=2(y-20)^2-k</cmath>intersect in four distinct points, and these four points lie on a circle with radius at most <math>21</math>. Find the sum of the least element of <math>S</math> and the greatest element of <math>S</math>.
  
 
==Solution==
 
==Solution==

Revision as of 16:50, 11 March 2021

Problem

Let $S$ be the set of positive integers $k$ such that the two parabolas\[y=x^2-k~~\text{and}~~x=2(y-20)^2-k\]intersect in four distinct points, and these four points lie on a circle with radius at most $21$. Find the sum of the least element of $S$ and the greatest element of $S$.

Solution

See also

2021 AIME I (ProblemsAnswer KeyResources)
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