Euler....IS_ALIVE
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 Apr18 comment Continuity of integral from x to x+1 of Lp function Hint : Holder . Mar24 comment Wave equation in three space dimensions The dot just means the $x$ variable. As you can see, the estimate only depends on the $t$ slice. Mar8 comment How do none of the of the polynomials have a degree 2? It is definitely wrong because $x^2$ is a degree 2 polynomial! Mar6 comment How to handle derivative of absolute value? Please look up the definition of weak derivative. The function might have a derivative in this sense. Mar6 comment Two norms $||.||_1$ and $||.||_2$ on a vector space $V$ are equivalent. This question has been answered at least 50 times on this site. Mar6 comment Find the limit of $\lim\limits_{x\rightarrow0}\frac{x}{\tan x}$. It was wrong. Now it's correct. Mar6 comment Find the limit of $\lim\limits_{x\rightarrow0}\frac{x}{\tan x}$. False? ${}{}{}{}$ Mar6 comment What decides if a Coxeter Group is “crystalline” or “non-crystalline”? This is going to be very hard to completely intractable depending on how much math you know. Do you know any group theory? Have you read the wikipedia article on Coxeter groups? It might be a little easier to read as an introduction than a paper. Feb27 comment About a theorem on stability of sytems of autonomous ODEs Is that word for word what the theorem says? It seems to be wrong then by your counterexample. Feb27 comment Solve 2nd order ordinary differential equation by Laplace transforms and convolution of their inverse functions. (5.6-40) Not correct. You can easily check by plugging it into your original equation. Feb26 comment How to solve $tx'(t) = (2t^2 + 1)x(t) + t^2$? This seems to be a simple 1d problem that you can solve with an integrating factor. Feb24 comment Given two increasing continuous functions $f,g$ prove that $(b-a) \int^b_a f(x)g(x) dx > \int^b_a f(x) dx \int^b_a g(x) dx$ You might want to check that your derivative is correct. Feb11 awarded Popular Question Jan13 comment Integral $\int\frac{(\sin(x))^2}{x^2+1} dx$ @Shadock You would have to cleverly introduce a parameter. Jan13 comment Calculating certain functions if only certain buttons on a calculator are permitted What do you know about triangles? Jan13 comment 2-transitively, formula What have you tried? Jan13 comment how to prove $f(x)= x^2$ is uniformly continuous on $\mathbb{N}$ @SRX That is in fact not true. Jan13 comment Integral $\int\frac{(\sin(x))^2}{x^2+1} dx$ This looks like a good candidate for differentiation under the integral. Dec15 comment A more general Bessel Function I swear it wasn't in that book when I was looking at it yesterday! Dec15 accepted A more general Bessel Function