Simon S
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 17h comment How do I tell if a differentiation and its antiderivative is unique? Proof read your question. As it stands, it is at least inconsistent leaning to incoherent. 2d revised Find $\int_0^{\infty} \frac{dx}{1+e^x}$ added 1 character in body 2d revised Find $\int_0^{\infty} \frac{dx}{1+e^x}$ added 57 characters in body 2d answered Find $\int_0^{\infty} \frac{dx}{1+e^x}$ Apr 27 comment Showing that $\sup\{|f(x)-f(y)|, x,y\in X\}= \sup \ f - \inf \ f$ small sign error Apr 26 revised Does the regularity of $\omega_{\alpha+1}$ need Axiom of Choice? edited title Apr 24 revised derivative of differentiable function added 33 characters in body Apr 24 answered derivative of differentiable function Apr 19 comment Why does the power series of $x + x^2 + x^3 …$ not equal to $x/(1-x)$ when x is larger than 1? Not "if" but "only if" .... Apr 13 awarded Popular Question Apr 13 comment How to compute $\lim\limits_{x\to \frac{\pi}{2}}\frac{\sin(x)-1}{x-\frac{\pi}{2}}$ without using the L'Hôpital's rule? Using the definition of derivative is logically prior to using L'Hopital's rule. Apr 12 comment Calculate trigonometric integral: $\int \sin(x)[\sec(2x)]^{3/2}dx$ This is slightly unsatisfactory but works: the primitive of that function is $\cos x \cdot (\sec(2x))^{1/2} + C$. Differentiate it to recover your integrand and then use those algebraic steps to figure out how to derive the primitive 'without' knowing the answer. Apr 4 comment What is the difference between $x+\sqrt{x^2}$ and $2x$? $\sqrt{x^2} = |x| \neq x$ for all $x$, only non-negative $x$. Apr 4 comment How to visualize topological differences between $\mathbb{R}P^{2n}$ and $\mathbb{C}P^n$ +1 Great answer Mar 29 revised Sketch $\dot x =x-y$, $\dot y= x+y$ on a phase portrait. deleted 16 characters in body Mar 28 answered Divergence of the sequence $n^2-100n$ as $n$ goes to $\infty$. Mar 27 comment What made the proof of the four color theorem on planes so hard? Bravo........... Mar 25 awarded Nice Question Mar 2 comment Correct set notation for “all integers which are not multiples of 7”? Yes but to my eyes at least this is the clearest answer as it uses the least technical notation. Feb 22 comment Differential Equation with biology! @Did Fair enough. Done