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Derivative

https://derivative.blog/

I'm an undergrad student in math at the University of São Paulo.

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Top Questions

A formal power series such that $f(f(x))=x$

formal-power-series asked Sep 28, 2022 at 18:45

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A function is of bounded variation if and only if the errors of its best approximation by trigonometric polynomials satisfy $\sum\frac{e_n}n<\infty$?

ca.classical-analysis-and-odes fourier-analysis approximation-theory asked Sep 22, 2022 at 23:51

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Is there a sequence so that $\sum |a_n|=\infty$ and $\sum a_n \cos(nx)$ and $\sum a_n \sin(nx)$ converge everywhere?

fourier-analysis absolute-convergence equidistribution asked Jul 2, 2022 at 23:51

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Is there a polynomial whose cube is a symmetric polynomial?

abstract-algebra symmetric-polynomials asked Sep 24 at 20:07

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Finding the asymptotic behavior of a function defined implicitly

calculus asymptotics implicit-function asked Nov 15, 2021 at 16:21

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How to find a root swapper polynomial?

polynomials contest-math asked Jul 18, 2021 at 13:56

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What's the smallest permutation group which has a subgroup not known to be a Galois group of a polynomial over $\mathbb Q$?

abstract-algebra finite-groups galois-theory asked Oct 29 at 12:48

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Top Answers

Find the sum of series $ \sum_{n=1}^{\infty}\frac{1}{n^3(n+1)^3}$

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Could it be generally proved that some positive integer is not of the form $x+y+2xy$?

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