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| bio | website | |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 1 year, 4 months |
| seen | May 16 at 9:20 | |
| stats | profile views | 315 |
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May 6 |
awarded | Caucus |
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Apr 25 |
revised |
What is the polar form of $ z = 1- \sin (\alpha) + i \cos (\alpha) $? added 2 characters in body |
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Apr 25 |
answered | What is the polar form of $ z = 1- \sin (\alpha) + i \cos (\alpha) $? |
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Apr 18 |
awarded | Disciplined |
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Apr 14 |
comment |
A question about the residue calculus Is this integral even convergent? |
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Mar 28 |
answered | Maximum value of $Z$ |
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Mar 11 |
comment |
How do I calculate the sum of $\sum_{k=1}^{\infty}\frac{(2-x)^k}{2^k\cdot k}$ in every x in (0, 4)? @vonbrand Yes it is, so what's your point? |
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Mar 11 |
answered | How do I calculate the sum of $\sum_{k=1}^{\infty}\frac{(2-x)^k}{2^k\cdot k}$ in every x in (0, 4)? |
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Mar 11 |
answered | Graph of a curve |
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Mar 11 |
comment |
Graph of a curve what have you tried? |
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Feb 27 |
comment |
Is this an even function? It isn't because $f(-x)=3+x\ne 3-x=f(x)$ for every $x \in [-1,0)\cup(0,1]$. |
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Feb 23 |
comment |
Prove that $\int_0^{\infty} \frac{\sin(2013 x)}{x(\cos x+\cosh x)}dx=\frac{\pi}{4}$ @MartinGales I think you are mixing things up, it is clear that the series $\sum_{k=1}^\infty(-1)^{k-1}$ does not converge, and I'm surprised you still believe it does. In fact, a necessary condition for the convergence of a series $\sum_{k=1}^\infty a_k$ is that $a_k \to 0$ which obviously is not satisfied. |
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Feb 21 |
comment |
Prove that $\int_0^{\infty} \frac{\sin(2013 x)}{x(\cos x+\cosh x)}dx=\frac{\pi}{4}$ @MartinGales I still don't see why the sum should be $1/2$. Are you using some "advanced calculus" to prove it? All I can see is that $s_{2n}=0$ and $s_{2n+1}=1$, and with my current knowledge of calculus, the latter tells me that this sum does not exist. |
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Feb 20 |
comment |
Prove that $\int_0^{\infty} \frac{\sin(2013 x)}{x(\cos x+\cosh x)}dx=\frac{\pi}{4}$ @MartinGales Yes, that's true only for $|x|<1$. |
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Feb 18 |
comment |
Prove that $\int_0^{\infty} \frac{\sin(2013 x)}{x(\cos x+\cosh x)}dx=\frac{\pi}{4}$ How do you prove that $\sum_{k=1}^\infty(-1)^{k-1}=\frac12$ although the partial sum $s_n:=\sum_{k=1}^n(-1)^{k-1}=(1-(-1)^n)/2$ does not converge? |
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Feb 18 |
comment |
Evaluation by methods of complex analysis $\int_{0}^{1} \frac{\ln(x+1)}{x^2+1} \mathrm{dx}$ @MårtenW I like the figure, which program did you use to draw it? |
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Feb 16 |
answered | Find a closure of the set |
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Feb 16 |
answered | Equality of 2 integrals (complex) |
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Feb 15 |
revised |
general solution to $u'=\left(\begin{matrix} -1 & 1\\ 0 & -1 \end{matrix}\right)u$. added 352 characters in body |
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Feb 15 |
revised |
general solution to $u'=\left(\begin{matrix} -1 & 1\\ 0 & -1 \end{matrix}\right)u$. edited body |
