Douglas S. Stones
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 Aug30 revised Find order of $xy$ provided $x^2=e, y^3=e$ and $yxy=xy^2x$ added 8 characters in body; edited tags; edited title Aug29 revised How is $\{ (1/n , 1 + 1/n) \}_{n \geq 1}$ a cover for $(0,2)$? edited title Aug29 comment Problem on directed graph involving $\gcd$ The question for strongly connected digraphs is now here. Aug29 comment Problem on directed graph involving $\gcd$ It looks like a counterexample to me. I wonder if this is a homework question; the lecturer might have a surprise when the assignments are returned. (I suppose the theorem would be true if there were no "incoherent" cycles.) Aug29 revised Problem on directed graph involving $\gcd$ Added drawing of graph Aug29 comment Problem on directed graph involving $\gcd$ What is the value of $p$ if $G$ has no cycles? Aug29 comment Calculate the Determinant? I neatened this answer up a bit, and also corrected the arithmetic. Aug29 revised Calculate the Determinant? Neatened it up; corrected arithmetic. Aug28 revised $\frac1a+\frac1b+\frac1c=0 \implies a^2+b^2+c^2=(a+b+c)^2$? edited tags Aug28 revised mean of two consecutive number helps proving both number equals.. edited tags Aug28 revised How do I explain the fallacy $\frac00=2$ in this case? edited tags Aug28 revised Critique on a proof by induction that $\sum_{i=1}^n i^2= n(n+1)(2n+1)/6$? re-titled; re-tagged Aug28 revised Simultaneous solution(s) to $a^2+4b^2+4ab=0$ and $a^2+4b^2+32+16a-8b=0$? re-titled; re-tagged Aug28 comment Have you seen this formula for factorial? This works then: $n!=\prod_{p^a \leq n} p^{\lfloor n/p^a \rfloor}$ where the sum is over all primes $p$ and $a \geq 1$ such that $p^a \leq n$. Aug28 comment Have you seen this formula for factorial? I'm wondering if it can be fixed by using something like "prime power p" or something similar. It's still not right, but a correction term perhaps could be introduced. Aug28 comment Have you seen this formula for factorial? Wrong, as in it's not right. E.g., $4!=24$ and $\prod_{p \leq 4} p^{\lfloor 4/p \rfloor}=2^2 \times 3=12$. Aug28 comment Have you seen this formula for factorial? The first formula is wrong for $n \geq 4$. Aug27 revised Area of a region between curves and a point. edited tags Aug27 revised Find an algorithm to compute $(1! \cdot 2! \cdot3!\cdots n! ) \,\%\, x$. edited tags Aug26 reviewed No Action Needed difference between $f(x)=0$ and $y=f(x)$.