How to capture between two characters in python using regex?
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We consider the differential equation $y'=x+y^2$ and for any $\eta \geq 0$ we denote by $\phi_\eta:(\alpha_\eta,\beta_\eta)\rightarrow\mathbb{R}$ the unique saturated solution of the Cauchy Problem $y'=x+y^2$, $y(0)=\eta$. I am required to do the change of variable $z(x)=y(-x)$ and I succeded here, obtaining $y'(-x)=y^2(-x)-x$ and so $z'(x)=x-z^2(x)$, then I was required to represent the $0-isocline$ and it was also simple as I obtained a parabolla and also I was required to write the equation of the tangent in the point $(0,\eta)$ which was also pretty simple as I obtained $\phi'_\eta(0)=\eta^2$ and the equation of the tangent is $y=\eta+\eta^{2}x$. Now, I am required to find $\phi^{(5)}_0(0)$( that $5$ indicates the number of differentiations), which puzzles me as I don't know the form of the solution and if it can be found out and also I am told to show that $\frac{1}{\eta}\geq\beta_\eta$ What I did not prove after the first edit : and that for $\eta &gt; 0$, $\alpha_\eta=-\infty$ and for the Cauchy problem $z'=x-z^2,z(0)=\eta$ the saturated solution is defined up to $+\infty$. At this last ones I am lost. Any help, please? Edit: I have passed beyond finding $\phi^{(5)}_0(0)$ and I think I did show that $\frac{1}{\eta}\geq\beta_\eta$, now it remains to prove the last questions. Setting "checked" for a checkbox with jQuery If parsing the output of ls is dangerous because it can break on some funky characters (spaces, \n, ... ), what's the best way to know the number of files in a directory?  I usualy rely on find to avoid this parsing, but similarly, find mydir | wc -l will break for the same reasons.  I'm working on Solaris right now, but I'm looking for a answer as portable across different unices and different shells as possible. Cell copy results in jaggy, aliased output Why don't we feel the subtle speed change of Earth's elliptical orbit? Earth's orbit is a slight ellipse, so to conserve momentum its speed increases when it is closest to the Sun. If the speed changes there is an acceleration. If there is an acceleration there is a force. Even if the change is small and gradual, wouldn't we experience a force because the Earth is so massive? PCA: Eigenvectors of opposite sign and not being able to compute eigenvectors with `solve` in R I am travelling to Athens, Greece, shortly, and have seen . Should I be worried? Should I cancel my trip?  Update  It's fine, taxis are currently on strike, but Syntagma Sqaure is fine: High-Swing Cascode Current Mirror I am currently dealing with current mirrors and came across the circuit shown below, a High-Swing Cascode Current Mirror. I read that this implementation, as the name suggests, has the advantage of a high voltage headroom, since the minimum potential at the drain terminal of M4 is: $$ V_{D4\_min}=V_{DS4}+V_{DS2}=(V_{GS4}-V_{TH})+(V_{GS2}-V_{TH}) $$ So the drain potential at M4 only needs to be twice the overdrive voltage, in case of same transistor dimensions, in order to hold M2 and M4 in saturation. But cannot this be said for many other cascode current mirrors, since that behaviour simply occurs by "stacking" together two transistors (M2 and M4)? Additionally, why is there a connection from the gate of M1 to the drain of M3? I have a hard time understanding whats going on in this circuit, help is greatly appreciated.    EDIT: A bias voltage source is setting the potential at the gate of M3/4. Sorry its not shown in the circuit.  EDIT 2: I just read that the mentioned bias voltage is implemented by a MOSFET in diode configuration, . For further discussion lets call it M5. I am struggling to find such languages $L_{1}$, $L_{2}$, and $L_{3}$ such that  $$ L_{1} \subseteq L_{2} \subseteq L_{3} $$ where $L_{1}, L_{3} \notin  \mathbb{R}$ and $L_{2} \in  \mathbb{R}$.  I know they exist, I need help finding them. intuition on the fundamental group of $S^1$ I am familiar with the proof that the fundamental group of the unit circle $S^1$ is $\mathbb Z$, yet I couldn't develop intuition for why it is true. For example, why would I fail if I try to find homotopy from a path that circles $S^1$ once to the path that stays at one point all the time? What brakes the continuity of such a homotopy? SVM for unbalanced data I want to attempt to use Support Vector Machines (SVMs) on my dataset. Before I attempt the problem though, I was warned that SVMs dont perform well on extremely unbalanced data. In my case, I can have as much as 95-98% 0's and 2-5% 1's.   I tried to find resources which talked about using SVMs on sparse/unbalanced data, but all I could find was 'sparseSVMs' (which use a small amount of support vectors).  I was hoping someone could briefly explain:   How well SVM would be expected to do with such a dataset   Which, if any, modifications must be done to the SVM algorithm What resources/papers discuss this How do I tell Finder to always show my Library folder on Mavericks? I thought there was a checkbox to suppress the hiding of my user Library folder on Mavericks, but I can't seem to find it. I appreciate hiding Library by default, but  have missed it being easily accessible.  How can I get the library folder to be visible in Finder, the Finder go menus / file save dialogs without needing to hold down shift? Can't create new folder from anywhere in Windows 7 I have this problem on two of my new laptops and can't seem to find a decent workable solution elsewhere in forum land. The problem is that on my Windows 7 Professional machines the right mouse button doesn't show the New Folder option and elsewhere as well (via Explorer) I'm unable to create new folders.   I'll be happy to get this tiny problem resolved and declare that Windows 7 is almost perfect! Thanks to all of you in advance for your contribution!  PS: None of the Vista solutions seem to work here!      Tried NewFolderFix.reg, didn't work - "Not all data was succesfully written to the registry. Some keys are open by the system or other processes."  Converted FolderFix.reg to .inf file and that worked.  Don't recall the problem appearing after an update.  MS answer to the explore process hanging (KB 972685) was to install the latest Visual C++ Update (vcredist.exe).  Nope. That didn't help either.  I haven't touched Silverlight since installation when Windows 7 hit the shelves. I tortured the RC installation before that, and never had problems there either.    UPDATE-  Logged back into Administrator account, still missing from there. Spent a bit more time looking instead of just fixing. Just yto make sure, logged back into my user account - still OK there.  Turns out the entries in HKCR\CLSID were the culprit here. Reg file wouldn't take again (as above) but inf file fixed it. This key was unable to be entered from regfile, or altered or deleted in Regedit (Permissions).   Don't quite understand why a common key in HKCR needed to be entered separately for each user.   Here is the file I used to fix it. Just copy into notepad, save as newfolderfix.inf, rt-click and select Install  ================================================================  [Version]  Signature=$Windows NT$  [DefaultInstall]  AddReg     =REGEntries.AddReg  [REGEntries.AddReg]  HKCR,"%String0%",,0x0,"CLSID_ExecuteFolder"  HKCR,"%String0%\InProcServer32",,0x0,"ExplorerFrame.dll"  HKCR,"%String0%\InProcServer32","ThreadingModel",0x0,"Apartment"   [Strings]  String0 = "CLSID\{11dbb47c-a525-400b-9e80-a54615a090c0}"  =============================================================   Thanks to others who helped point me in the right direction. Why don't the Google Docs CTRL + ALT shortcuts work? I'm currently using Google Docs, but when I try to use the keyboard shortcuts like Ctrl+Alt+M it gives µ instead.    Is Chrome (9) overruling Google Docs in some way?  How can I get these shortcuts working?  I'm using Chrome dev 9 on a Dutch Windows 7 with a US-layout keyboard hyperlink name with biblatex authoryear (biblatex 1.4b) Why was Sirius ever convicted? Sirius himself says at some point in Goblet of Fire that Crouch pushed through legislation to have him convicted and thrown in Azkaban without a trial.  There seems to be a general consensus, specifically voiced by Fudge but also implicit in Crouch pushing through this legislation, that Sirius was considered one of Voldemort’s innermost, most dangerous, and most trusted right hands. Easily as inner-circle as the Lestranges, for example.  It seems quite unlikely to me that someone so close to Voldemort should not be a Death Eater—apart from Fenrir Greyback (who I would think is much less inner-circle), I do not recall hearing of any of Voldemort’s important servants not being Death Eaters.  As far as canon describes, all Death Eaters have the Dark Mark magic-tattooed on their arm, to be used as a way for Voldemort to summon them to him. Considering that Karkaroff, who had definitely burnt all his Death Eater bridges, still had the Dark Mark, I am assuming that getting rid of the Mark is not possible: once it’s on, it stays on.  Yet, as Hermione points out in Order of the Phoenix (ch. 16, “In the Hog’s Head”), Sirius does not have the Dark Mark.  So why was he so swiftly convicted and locked up? I mean, I know they were eager to be seen to be doing something (as Fudge keeps pointing out is his excuse for most of the miscarriages of justice he commits)… but seriously, did no one think to check if Sirius actually had a Dark Mark on his arm or not? Did the Ministry of Magic not even know at the time that all Death Eaters had the Mark? Or were they just happy to accept—without the scrutiny of a full trial—that a non-Death Eater would commit mass murder for a Voldemort who was presumed defeated? MySQL Error 1153 - Got a packet bigger than 'max_allowed_packet' bytes How to determine if string contains specific substring within the first X characters How do I get started creating an Ubuntu Desktop App? How to make Outlook 2010 minimize when I try to close it? When clicking the X button or ALT+F4, how can I get Outlook to minimze to the tray instead of close?  Several programs have this behavior, and it's annoying that Outlook behaves different...