robjohn

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The Mean Square
(with one standard deviation and several unusual ones)

aka Rob Johnson

$\LaTeX$ support for Chat

Where would math be if Fermat had Post-it notes?

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1,631 Answers

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51	How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$?
33	How to prove a trigonometric identity
29	Find a $4\times 4$ matrix $A$ where $A\neq I$ and $A^2 \neq I$, but $A^3 = I$.
29	Computing $\zeta(6)=\sum\limits_{k=1}^\infty \frac1{k^6}$ with Fourier series.
27	Question about a rotating cube?

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63,238 Reputation

+10	Prove that none of $\{11, 111, 1111,\dots \}$ is the perfect square of an integer
+10	How can evaluate $\lim_{x\to0}\frac{\sin(x^2+\frac{1}{x})-\sin\frac{1}{x}}{x}$
+17	What does an expression $[x^n](1-x)^{-1}(1-x^2)^{-1}(1-x^3)^{-1}(1-x^4)^{-1}…$ mean?
+15	computation of $\int_0^T \frac{\sin (t)}{t} dt$

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1 Question

votes activity newest

26	How to sum this series for $\pi/2$ directly?

258 Tags

1k calculus × 276	472 limit × 113
940 sequences-and-series × 224	429 trigonometry × 95
689 real-analysis × 192	417 complex-analysis × 128
550 integral × 114	307 integration × 74
544 homework × 191	291 inequality × 75

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