Hagen von Eitzen
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168,627
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 Nov 18 answered How to prove distributive property of a determinant? Nov 18 comment Composition of monotonic and measurable function is measurable @StefanHansen Warning: When talking about Lebesgue-measurability, we consider different sigma-algebras on domain and codomain! Nov 18 answered Composition of monotonic and measurable function is measurable Nov 18 comment How do I create this simple graph working backwards? What's wrong with linear interpolation? And how do you predict the 6 moth value? Nov 18 answered If $p$ is the prime of the form $4k+1$. Prove that $(1/p)+(2/p)+(3/p)+\ldots+ (P/p) = 0$ Nov 18 comment Proof of a certain lemma in geometry You don't see that $F$ is the tangency point of the excircle? Or you don't see how this implies $BD=CF$? Nov 18 comment If $p$ is the prime of the form $4k+1$. Prove that $(1/p)+(2/p)+(3/p)+\ldots+ (P/p) = 0$ I assume that these are Jacobi symbols, not just fractions, so your transformation of the LHS is not valid Nov 17 comment Proving that $\frac{\pi ^2}{p}\neq \sum_{n=1}^{\infty }\frac{1}{a_{n}^2}$ By the greedyness of the algorithm,the error of the partial sum after adding $\frac1{n^2}$ is known to be less than $\frac1{(n-1)^2}-\frac1{n^2}\approx\frac3{n^3}$. For your example, this estimate gives $\approx 5.6\cdot 10^{-33}$, not much larger than the actual error. Nov 17 comment Finding the positive integer numbers to get $\frac{\pi ^2}{9}$ The bound for the tail of $\sum\frac1{n^2}$ can of course also be obtained by comparison with the telescope $\sum(\frac1n-\frac1{n+1})=\sum\frac1{n^2+n}$ Nov 17 comment Need hints/resources to solve this system of equations (seems like a loop) To finish, you only need that $0<\ln x< x-1$ for $x>1$ and $0>\ln x>x-1$ for \$0