Difference between revisions of "2022 SSMO Relay Round 5 Problems"

(Created page with "==Problem 1== Consider an <math>8\times 8</math> chessboard with a knight in one of the center squares. The knight may move in an <math>L</math>-shaped fashion, going two squ...")
 
 
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==Problem 3==
 
==Problem 3==
  
Let <math>T=</math> TNYWR, and let <math>a_k=\cis\left(\frac{k\pi}{T+1}\right)</math>. Suppose that <cmath>\sum_{k=1}^{T+1} \frac{|a_{2k}+a_{2k+2}-a_{2k-1+T}|}{|a_{2k+1}-( a_{2k}+a_{2k+2})|}</cmath> can be expressed in the form of <math>a+b\cos(\frac{\pi}{c})</math>, where <math>\cis(x) = \cos(x) + i\sin(x)</math>. Find <math>a+b+c</math>.  
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Let <math>T=</math> TNYWR, and let <math>a_k=\text{cis}\left(\frac{k\pi}{T+1}\right)</math>. Suppose that <cmath>\sum_{k=1}^{T+1} \frac{|a_{2k}+a_{2k+2}-a_{2k-1+T}|}{|a_{2k+1}-( a_{2k}+a_{2k+2})|}</cmath> can be expressed in the form of <math>a+b\cos(\frac{\pi}{c})</math>, where <math>\text{cis}(x) = \cos(x) + i\sin(x)</math>. Find <math>a+b+c</math>.  
  
 
[[2022 SSMO Relay Round 5 Problems/Problem 3|Solution]]
 
[[2022 SSMO Relay Round 5 Problems/Problem 3|Solution]]

Latest revision as of 20:59, 31 May 2023

Problem 1

Consider an $8\times 8$ chessboard with a knight in one of the center squares. The knight may move in an $L$-shaped fashion, going two squares in one direction and one square in a perpendicular direction, but cannot go outside the chessboard. How many squares can the knight reach in exactly two moves?

Solution

Problem 2

Let $T=$ TNYWR, and let $S=\{a_1,a_2,\dots,a_{2022}\}$ be a sequence of 2022 positive integers such that $a_1\le a_2\le \cdots \le a_{2022}$ and $\text{lcm}(a_1,a_2,\dots,a_{2022})=70T$. Also, $\text{gcd}(a_i,a_j)=1$ for all $1\le i<j\le2022$. Find the number of possible sequences $S$.

Solution

Problem 3

Let $T=$ TNYWR, and let $a_k=\text{cis}\left(\frac{k\pi}{T+1}\right)$. Suppose that \[\sum_{k=1}^{T+1} \frac{|a_{2k}+a_{2k+2}-a_{2k-1+T}|}{|a_{2k+1}-( a_{2k}+a_{2k+2})|}\] can be expressed in the form of $a+b\cos(\frac{\pi}{c})$, where $\text{cis}(x) = \cos(x) + i\sin(x)$. Find $a+b+c$.

Solution