# ISI2011-PCB-A-4a

2 votes
110 views
Consider six distinct points in a plane. Let $m$ and $M$ denote the minimum and maximum distance between any pair of points. Show that $M/m \geq \sqrt{3}$.

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303 views
An $n \times n$ matrix is said to be tridiagonal if its entries $a_{ij}$ are zero except when $|i&minus;j| \leq 1$ for $1 \leq i, \: j \leq n$. Note that only $3n &minus; 2$ entries of a tridiagonal matrix are non-zero. Thus, an array $L$ of size $3n &minus; 2$ ... a tridiagonal matrix. Given $i, j$, write pseudo-code to store $a_{ij}$ in $L$, and get the value of $a_{ij}$ stored earlier in $L$.