Mathematics

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Jun 14, 2017 05:17
is that true?
Jun 14, 2017 05:17
Quick question, for a matrix norm
$$
\frac{1}{\Vert A \Vert} = \sup \frac{\Vert x \Vert}{ \Vert A x\Vert}
$$
Jun 14, 2017 05:14
Quick question, for a matrix norm
\[
\frac{1}{\Vert A \Vert}
\]
Nov 4, 2014 02:43
But this seems like since this holds for all $0 < \varepsilon$ it should imply that $m(E-F) = 0$
Nov 4, 2014 02:41
It usually presented in the context of "There is a closed set $F$ in $E$ for which $f = g$ on $F$ and $m(E-F) < \varepsilon$
Nov 4, 2014 02:40
`Quick question: Does Lusin's Theorem imply that for a real valued measurable function $f$ on $E$. That there is a continuous function $g$ such that $f=g$ almost everywhere on $E$?
Nov 22, 2013 03:04
residue calculator
Nov 22, 2013 03:03
how would I find the sum of the residues of \frac{1}{1+z^3}
Oct 3, 2013 17:45
how much differential equations is required for Real Analysis/ Function Analysis?
Oct 1, 2013 05:16
Notice that by partial fraction decomposition we have,

$$
\int_{\gamma} \frac{1}{z^2-2z}\ dz = \frac{1}{2}\int_{\gamma} \frac{1}{z}\ dz - \frac{1}{2} \int_{\gamma} \frac{1}{z-2}\ dz.
$$

We know by the Fundamental Theorem of Calculus for Contour Integrals that since $\gamma$ is a closed path and since the principal branch of the log is analytic on some open set containing $\gamma$ then $(1/2) \int_{\gamma}(1/z)\ dz = 0$. For the other part we can see, that in a similar fashion of Problem 2 part (c), we parameterize $\gamma: [0,2\pi] \to \mathbb{C}$ as $ \gamma(\theta)= e^{i\theta} + 2$ a
Oct 1, 2013 05:16
Is this complex valued integral correct?
Sep 23, 2013 04:06
Im looking for something that is a little bit rigorous, not a general-public level book
Sep 23, 2013 04:06
Such as transcendental numbers, non computable irrationals, transfinite numbers, etc.
Sep 23, 2013 04:05
Speaking of books, does anyone know of a book about the more exotic number?
Sep 23, 2013 04:04
@Emrakul However, generally books of this style are very out of fashion. My personal recommendation is when reading a book read the theorem and cover up the proof, try to prove it yourself, if you cant get it, read a line of the proof, try to prove again, etc
Sep 23, 2013 04:03
@Emrakul There is one by I.M Yaglom called Convex Figures
Sep 10, 2013 16:31
@Kasper Unless you are working in $\mathbb{R}^n$ i dont think you should need to prove the infinite dimensional case
Sep 10, 2013 14:04
also think of $\sum a_n$ in relation to $\sum a_n^2$ and yeah use the CS Inequality
Sep 10, 2013 14:03
Kasper, cases
Sep 10, 2013 14:01
Is this the correct?

$(-1)^{i} = e^{i \log(-1)} \cdot e^{-2\pi n i}
= e^{-\pi} \cdot e^{-2\pi n}
= e^{-\pi (1 + 2n)}
$
Apr 25, 2013 11:32
but, thats life.
Apr 25, 2013 11:32
Also i had way to little time. This semester. I am sure I could have gotten an A if I had more time.
Apr 25, 2013 11:32
@Lord_Farin Yeah
Apr 25, 2013 11:27
I was really scared of that course. It was harder for me than analysis
Apr 25, 2013 11:26
Yes!
Apr 25, 2013 11:26
which is great considering I was close to a C
Apr 25, 2013 11:26
And ended up with a B in the calls
Apr 25, 2013 11:26
@Lord_Farin I ended up getting an 81 on my algebra final
Apr 25, 2013 11:25
@Lord_Farin Hey
Apr 25, 2013 00:34
well i think I did ok on my algebra exam
Apr 24, 2013 19:13
@shobon But i just thought of this, and I am quite should that I this was not explicitly written down in my book anywhere. I was wondering if there is some very obvious reason.
Apr 24, 2013 19:12
@shobon because I dont have time really
Apr 24, 2013 19:11
If $|a|=n$ then in general shouldn't it be true that $Z_n \approx \langle a \rangle$?
Apr 24, 2013 18:53
Is that proof right by the way?
Apr 24, 2013 18:53
@Lord_Farin ok
Apr 24, 2013 18:52
Take, $aha^{-1}$ then let $a = (34)$.
Then $aha^{-1} = (34)h(43)$. If I plug in (3) I get
$(34)h4$ and if h and (4) are disjoint so they dont commute and its not in $H$
Apr 24, 2013 18:49
Wait, it IS normal?
Apr 24, 2013 18:49
Basically any permutation that does not "touch" 3 is in $H$
Apr 24, 2013 18:48
@Lord_Farin $|H| = 4!$ right?
Apr 24, 2013 18:46
what is $[5]$?
Apr 24, 2013 18:45
is that "plugging in 3" to the permutation $a$?
Apr 24, 2013 18:45
what does the notation $a(3)$ mean?
Apr 24, 2013 18:45
"Consider the set $H = \{a \in S_5 \mid a(3) = 3\}$. Is $H$ a subgroup of $S_5$, is it normal?"
Apr 24, 2013 18:44
can some one clarify this for me
 

 Ten fold

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Mar 26, 2017 21:59
The r function quantile is for sample quantiles
Mar 26, 2017 21:58
How can I determine the quantile function given only the CDF?
 
Oct 22, 2013 09:51
@egreg I am using the both of those commands, any idea why that might still be happening?. Even more strange, when i remove the \usepackage[T1]{fontenc}, and just keep \uspackage{lmodern}it seems to work fine
Oct 18, 2013 07:29
for comparison the F(y) = 1/5, is in math times which renders fine. Any idea why this is?
Oct 18, 2013 07:28
Oct 18, 2013 07:28
so for some reason with I tried to use the latin modern fonts, there look terrible. Almost photo copied