Ewan Delanoy
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 8h comment A monotonically increasing series for $\pi^6-961$ to prove $\pi^3>31$ @GerryMyerson A reasonable and natural question in this context is : can we write $\pi^6-961$ as a sum of the form $\sum_{k=1}^{n} \frac{1}{P(k)}$ where $P$ is a polynomial with nonnegative, rational coefficients. This is the case for the examples given in the OP Feb 6 comment Is it possible to find a perfect cube like 111…11? No, it is still not correct. See my comment starting with "The correction propagates" above Feb 6 comment Is it possible to find a perfect cube like 111…11? The correction propagates : you should write $10(900m^3+270m^2+27m-10^{n-1}+2)-10=0$ rather than $10(900m^3+270m^2+27m-10^{n-1}+2)-1=0$, and $10r-10=0$ rather than $10r-1=0$ Jan 31 awarded Notable Question Jan 31 comment Prove $\frac{2ab}{a+b}\leq\sqrt {ab}$ It's mostly correct (except you should write it backwards and replace < with <=) but a little complicated. It is simpler to square each side, simplify by $ab$ and get rid of denominators Jan 30 answered Factorize $2a^3 - b^3 - c^3$ Jan 27 answered $\mathbb{Q}(\sqrt[3]{17})$ has class number $1$ Jan 27 accepted Algebraic integers divided by a prime Jan 27 revised Algebraic integers divided by a prime added 1 character in body Jan 27 asked Algebraic integers divided by a prime Jan 26 comment Prove that $\frac{a}{b+2c+3d}+\frac{b}{c+2d+3a}+\frac{c}{d+2a+3b}+\frac{d}{a+2b+3c} \geq \frac{2}{3}.$ This is essentially the same solution as Gordon's. Jan 15 answered Prove that $X,Y,Z$ lie on a single line. Jan 9 comment Matrices A+B=AB implies A commutes with B @Freeze_S There is no flaw. In general the polynomial (which I call $Q$) will have nothing to do with a Taylor expansion. Jan 5 reviewed Approve Find the determinant of the following matrix Jan 4 asked Polynomial whose roots are not integers but almost so Dec 21 answered Proving $(ax+by-1)^2 \ge (x^2+y^2-1)(a^2+b^2-1)$ Dec 21 revised Canonical colorings over $\omega$ added 134 characters in body Dec 21 answered A sequence of quadratic polynomials Dec 18 comment Show that $\lim\limits_{r\to\infty} \textrm{\{} \|x-ru\|-\|y-ru\| \textrm{}\} = \left$ It is clearer now, indeed. Dec 18 comment Show that $\lim\limits_{r\to\infty} \textrm{\{} \|x-ru\|-\|y-ru\| \textrm{}\} = \left$ The last step is not very clear.