Conditional statement in a function for PS1 are not re-evaluated
PS1='$(pwd)' why this works and why is this different from PS1=$(pwd)
Product of path connected spaces is path connected Will product of path connected topological spaces be necessarily path connected? Why or why not?  Give me some hints. Thank you. $$A=\begin{array}{ccc} 0 &amp; 1/2 &amp; 0 &amp; \cdots &amp; 0 \\ 1/2 &amp; 0 &amp; 1/2 &amp;\cdots&amp; 0\\ 0 &amp; 1/2 &amp; 0 &amp; \cdots &amp; 0\\ \vdots &amp; \vdots &amp; \vdots &amp;\ddots &amp; 1/2\\ 0 &amp; 0 &amp; 0 &amp; 1/2 &amp; 0 \end{array}$$  I need to know the spectral radius of $A$ in function of the dimension of the matrix $n$. I know only one way to know the spectral radius, using the definition I find all eigenvalues and then find the maximum. but it very hard if $n$ is changing. Some help please!  I did some iteration by   $$det(\lambda I-A)$$  $$n=2 \quad r=\frac{\sqrt{1}}{2}$$ $$n=3 \quad r=\frac{\sqrt{2}}{2}$$  for $n=2$ and $n=3$ are correct.  and if we take this rule, for   $$n=5\quad \quad r=\frac{\sqrt{4}}{2}$$  but this isn´t true since I know radius for this matrix should be $&lt; 1$ and if we take this rule  for $n=5$ we have  $$\frac{\sqrt4}{2}=1$$   Some hint? What is proper way to update D8 DEV? Help identifying an error type "tried to help me learning" I have a friend from Russia who is trying to learn English and recently used the sentence "He tried to help me learning..." (implied: the English language)  It is obviously wrong and I corrected it telling her that she was supposed to say: "He tried to help me learn.", but I have a hard time explaining to her why it is incorrect since I'm not an expert on grammar either.  Is it a case of confusing the present simple and present continuous or does it have something to do with gerunds and infinitives? Any help would be highly appreciated! Adding the PHP json extension I don't know so much about coordinate systems...  In my office we use to deal with spatial data coming from archaeological sites. Each site has its own x-y-z coordinate system (GCS). Three simple ortogonal cartesian axis. In the last years we have been managing this spatial data through GIS software (ArcGIS), without using specific coordinate system (just leave it as "undefined")  I'd like to know if there exisits any GCS designed to deal with such datasets using simple cartesian orthogonal axis, without grid distortions of the typical GCS. In addition, I'd like to know if this system is suitable for using it in an online mapping application.  By the way, we manage 2D (ArcMap) and 3D (ArcScene) environments and work with "mm" as length base unit.   If such a thing doesn't exists, maybe someone knows how to create it. I'tm trying to show in SQLcmd window the results of these queries:  SELECT SYSDATETIME() AS "date";  PRINT 'EXTRAÍDO POR:' SELECT SUSER_NAME() AS "Owner"  PRINT 'PASSWORD SETTINGS'; exec xp_loginconfig;  PRINT 'PASSWORD SETTINGS'; select * from sys.sql_logins;   And using this command in SQLcmd:  sqlcmd -S myServer -i inputpath -s, -o outputPath(like C:\log.xls) -e   So the sqlcmd output the file and does not show nothing in sqlcmd screen. How can i print these "Print" commands in the sqlcmd screen? (command promt).  When I run it on SSMS works well, like:  (1 row affected) OWNER:  (1 row affected) PASSWORD SETTINGS  (8 rows affected) PASSWORD SETTINGS  I would like to show in the prompt command this, like in the SSMS.  Thanks! What equipment and settings do I use for panning shots of moving objects? How do you go about getting great panning shots of things like cars and bicycles so that the background is nice and blurred but the target is sharp as can be. I have tried on many occasion to do panning shots and I just can't get the setup right.  What lens setup, shutter speed would be a good place to start? How would one throw an unwilling creature? My bugbear barbarian, who can lift about double the weight of a wolf, wanted to throw the wolf at a second wolf. How would we go about doing that given existing rules options? Is it logically correct to assert that the expectation of the momentum $$\langle \hat p \rangle=0$$ for any bound state because it is bound to some finite region? What is the physical interpretation of the fact that $$\langle \hat p \rangle=0$$ in an energy eigenstate $\psi_n(x,t)$  but $$\langle \hat p \rangle\neq0$$ in some superposition state $$\psi(x,t)=c_m\psi_m(x,t)+c_n\psi_n(x,t)~?$$ Here $\psi_n(x,t)$ the eigenstates of the Hamiltonian, for example, in the problem of particle in a box (say). Isekai manga where the mc is reincarnated through his own magic The MC reincarnated himself through his own magic after his party defeated the demon king. Before he used his magic to do so, he took the daughter from the demon king and traveled with her over the world. After he used his reincarnation magic he was born in a noble family where the daughter of the demon king is now working as a maid in this family. He also has an older/younger (not sure) brother. Through his knowledge he starts his training of body, swordsmanship and magic as a baby. Years later his brother wants to play with him but he denies him every time. But one day he accepts it to play tag. His brother can't catch him. After that, he requests from the mc to teach him his magic. He denied again, but made an offer. Only when he can catch him, would he teach him his magic. I hope I'm not mixing up different mangas. Problem: If   $$C_0+\frac{C_1}{2}+\cdots + \frac{C_{n-1}}{n}+\frac{C_n}{n+1} =0,$$  where $C_0,...,C_n$ are real constants, prove that the equation  $$C_0+C_1x+\cdots +C_{n-1}x^{n-1}+C_nx^n=0$$  has at least one real root between $0$ and $1$.  Source: W. Rudin, Principles of Mathematical Analysis, Chapter 5, exercise 4. Unable to solve equation for a variable by any method Underfull \hbox in bibliography I am getting lots of "Underfull \hbox" warnings that point to the *.bbl file. It looks like these messages appear only when URLs are very long, like in the below example:  @techreport{nistguidesec,   author    = {Wayne Jansen and Timothy Grance},   title     = {Guidelines on Security and Privacy in Public Cloud Computing},   month    = {January},   note     = {Draft Special Publication 800-144. Available at \url{http://csrc.nist.gov/publications/drafts/800-144/Draft-SP-800-144_cloud-computing.pdf}}, }   In the produced PDF text is correctly hyphened and links are correctly split over several lines (I am using hyperref package)  How can I avoid annoying warning messages about "underfull \hbox" pointing to bibliography? Is there a formula for $(1+i)^n+(1-i)^n$? What is the difference between '->' (arrow operator) and '.' (dot operator) in Objective-C? Plot x=3 in PGFPlots Trying to remember a book that had people (I think they turned white?) segregated into a compound Make account merges propagate to chat Possible Duplicate:    I am using 10.04 LTS - Lucid Lynx. I shutdown the computer while a software update was running. Then after I restarted my computer and while the update manager was running, I got this error:  Could not download all repository indexes The repository may no longer be available or could not be contacted because of network problems. If available an older version of the failed index will be used. Otherwise the repository will be ignored. Check your network connection and ensure the repository address in the preferences is correct. GPG error: http://toolbelt.herokuapp.com ./ Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C927EBE00F1B0520 Failed to fetch  http://ppa.launchpad.net/rabbitvcs/ppa/ubuntu/dists/**DISTRIBUTION**/main/binary-i386/Packages.gz 404  Not Found   I went through the answers to  and I tried this $ sudo launchpad-getkeys  Please wait... launchpad-getkeys is running an update so it can detect the missing GPG keys Trying to import all the missing keys gpg: requesting key 0F1B0520 from hkp server keyserver.ubuntu.com gpgkeys: key C927EBE00F1B0520 not found on keyserver gpg: no valid OpenPGP data found. gpg: Total number processed: 0 launchpad-getkeys has finished importing all missing GPG keys.  Try running sudo apt-get update - you shouldn't see any key  errors anymore  But when I run sudo apt-get update again, it again shows that the key was not found on the keyserver. How to solve this problem?