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visits member for 1 year, 6 months
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Undergraduate at University of Lund, Mathematics


9h
comment Evaluate a limit using integral
I thought that the limit was $$\lim_{n\rightarrow \infty}\lim_{x\rightarrow 1 -} \sum_{k=1}^{2n}\frac{(-x)^{k-1}}{k}$$ I think the real issue here lies in the fact that we actually can interchange the limits in your suggested way, but how does one motivate such a step?
Jan
30
answered multivariable limit problem
Jan
27
revised Integral $\int^{\frac{\pi}{2}}_{-\frac{\pi}{2}} \ln(1+c\sin x) dx$, where $0<c<1$
deleted 185 characters in body
Jan
27
answered Integral $\int^{\frac{\pi}{2}}_{-\frac{\pi}{2}} \ln(1+c\sin x) dx$, where $0<c<1$
Jan
20
comment Prove $\int_{0}^{1} |\frac {f^{''}(x)}{f(x)}| dx \geq 4$
What about $f(x)=x(x-1)$ isn't that a counterexample?
Dec
30
awarded  Curious
Dec
29
asked Evaluating a sum $-\zeta'(2)$
Dec
24
comment A not complete metric space?
We know that $\mathbb{R}$ with the usual metric $d(x,y) =|x-y|$ is a complete metric space. Since the exponential function is continuous, then we usually would expect the $|e^{x}-e^{y}|$ should be small aswell... But maybe it has something to so with uniformness..
Dec
24
comment A not complete metric space?
Is your statement even true?
Dec
10
accepted Ideal in a ring of continuous functions
Dec
9
awarded  Caucus
Nov
26
answered Fourier Transform of $\exp(-t)$
Nov
20
comment Functional inequalities involving cubing and incrementing
$f(x) = nx$, for $n>1$ ?
Nov
13
answered Proof using exhaustion $n^4 - 1$ is divisible by $5$ where $n$ is not divisible by $5$.
Nov
9
comment How to prove that the function $\tan(x)1_{(0,\pi/2)}$ lies in $L^p$ for $p\in (0,1)$?
I split the interak from $[0,1]$ and $[1,\infty)$, then i make the sub. $u\rightarrow \frac{1}{u}$ on the integral over $[1,\infty)$
Nov
9
comment How to prove that the function $\tan(x)1_{(0,\pi/2)}$ lies in $L^p$ for $p\in (0,1)$?
I split the interval from
Nov
9
answered How to prove that the function $\tan(x)1_{(0,\pi/2)}$ lies in $L^p$ for $p\in (0,1)$?
Oct
27
comment primitive root mod25
The order of any element that is relatively prime to 25 must divide $\phi(25)=20$, which is the total order, since there are $\phi(25)$ elements that are relatively prime to 25.
Oct
26
awarded  Custodian
Oct
26
reviewed Approve How to evaluate $\int_0^{\infty} \bigg(\frac{e^{-x}}{\sinh(x)} - \frac{e^{-3x}}{x}\bigg) \; dx$