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Difference between revisions of "G285 2021 Fall Problem Set"

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==Problem 2==
 
==Problem 2==
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Let <math>\triangle ABC</math> be a right triangle with right angle at <math>B</math>, and <math>AC=12</math>. Let <math>D</math> denote the intersection of the cevian dropped from <math>B</math> onto <math>AC</math> such that <math>DA=DC</math>. If the reflection of point <math>B</math> across <math>D</math> lies on the circumcircle of <math>\triangle ABC</math> as <math>E</math>, and <math>\sin(BAC)<\frac{5}[8}</math>, find the smallest possible integer radius of the circumcircle of <math>\triangle EBA</math>.
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Let <math>\triangle ABC</math> be a right triangle with right angle at <math>B</math>, and <math>AC=12</math>. Let <math>D</math> denote the intersection of the cevian dropped from <math>B</math> onto <math>AC</math> such that <math>DA=DC</math>. If the reflection of point <math>B</math> across <math>D</math> lies on the circumcircle of <math>\triangle ABC</math> as <math>E</math>, and <math>\sin(BAC)<\frac{5}{8}</math>, find the smallest possible integer radius of the circumcircle of <math>\triangle EBA</math>.

Revision as of 00:35, 9 July 2021

Welcome to the Fall Problem Set! There are $15$ problems, $10$ multiple-choice, and $5$ free-response.

Problem 1

Larry is playing a logic game. In this game, Larry counts $1,2,3,6, \cdots$, and removes the number $r+p$ for every $r$th move, skipping $r+jp$ for $j \neq 0 \mod 3$, and then increments $p$ by one. If $(r,p)$ starts at $(1,3)$, what is $r+p$ when Larry counts his $100$th integer? Assume $\{r,p,j \} \in \mathbb{N}$

Problem 2

Let $\triangle ABC$ be a right triangle with right angle at $B$, and $AC=12$. Let $D$ denote the intersection of the cevian dropped from $B$ onto $AC$ such that $DA=DC$. If the reflection of point $B$ across $D$ lies on the circumcircle of $\triangle ABC$ as $E$, and $\sin(BAC)<\frac{5}{8}$, find the smallest possible integer radius of the circumcircle of $\triangle EBA$.

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