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 Mar19 awarded Popular Question Mar11 awarded Popular Question Feb19 awarded Popular Question Feb15 comment Examples of apparent patterns that eventually fail Sorry for being three years late, but I don't see what the deal is with the $\sqrt{163}$ sum. I mean, it's pretty cool, but what does it have to do with the question? Feb13 comment How is SO(2) compact according to this definiton? MathWorld's definition doesn't make a lot of sense, because usually you can't cover the whole group (or manifold in general) with a single coordinate chart. Jan26 awarded Nice Question Jan12 awarded Good Answer Dec15 comment How to calculate$\int_0^{\infty} e^{-x^2} \sin x dx$ in the most simple way @Lucian: My comment is not as useful as I thought it would be. It would work if the limits were $\pm \infty$ (of course, the integral would be zero), but it doesn't work here because after completing the square, the limits of integration are not simple. It does let you get to the Dawson function quickly, but I thought you could get a closed form solution. Dec15 comment How to calculate$\int_0^{\infty} e^{-x^2} \sin x dx$ in the most simple way Use $\sin x = (e^{ix}-e^{-ix})/2$. Dec13 awarded Nice Question Nov25 reviewed Approve Consider the following limit: $\lim_{n \to \infty } \frac{\ln(1+n)-\ln(n^{2})}{\sin(1/n)}$ Nov13 accepted Does the matrix exponential take open sets into open sets? Nov13 comment Does the matrix exponential take open sets into open sets? @m.g.: Well, that was simple. You should post that as an answer. Nov13 comment Does the matrix exponential take open sets into open sets? @Jack: what about $x^2$ on $(-1,1)$? Nov13 asked Does the matrix exponential take open sets into open sets? Nov6 awarded Nice Question Oct24 awarded Yearling Oct23 awarded Notable Question Oct8 comment How do I take the limit of this function? You must be doing something wrong: when I put in $2.1$, $2.01$, $2.001$, I get $15$, $150$, $1500$, etc. Sep30 awarded Explainer