Steam, missing 32bit libs but it won't install Steam needs to install these additional packages: libgl1-mesa-dri:i386, libgl1-mesa-glx:i386, libc6:i386  [sudo] password for user: E: The method driver /usr/lib/apt/methods/https could not be found.  Reading package lists... Done Building dependency tree       Reading state information... Done Package libc6:i386 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source However the following packages replace it:   tzdata libdb1-compat locales libc-bin initscripts  Package libgl1-mesa-glx:i386 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  Package libgl1-mesa-dri:i386 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source However the following packages replace it:   libgl1-mesa-glx  W: Duplicate sources.list entry http://dl.google.com/linux/chrome/deb/ stable/main amd64 Packages (/var/lib/apt/lists/dl.google.com_linux_chrome_deb_dists_stable_main_binary-amd64_Packages) W: You may want to run apt-get update to correct these problems E: Package 'libgl1-mesa-dri:i386' has no installation candidate E: Package 'libgl1-mesa-glx:i386' has no installation candidate E: Package 'libc6:i386' has no installation candidate Press return to continue:   When I type in sudo apt-get update:   user@chrubuntu:~$ sudo apt-get update [sudo] password for user: E: The method driver /usr/lib/apt/methods/https could not be found.  When I type in sudo apt-get install ia32-libs user@chrubuntu:~$ sudo apt-get install ia32-libs Reading package lists... Done Building dependency tree        Reading state information... Done Package ia32-libs is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source However the following packages replace it:   lib32z1 lib32ncurses5 lib32bz2-1.0  W: Duplicate sources.list entry http://dl.google.com/linux/chrome/deb/ stable/main amd64 Packages (/var/lib/apt/lists/dl.google.com_linux_chrome_deb_dists_stable_main_binary-amd64_Packages) W: You may want to run apt-get update to correct these problems E: Package 'ia32-libs' has no installation candidate user@chrubuntu:~$    P.S. I'm a total newbie at ubuntu/linux
"method driver /usr/lib/apt/methods/https could not be found" update error sudo apt-get update E: The method driver /usr/lib/apt/methods/https could not be found. michael@Ubuntu:~$ sudo apt-get clean michael@Ubuntu:~$ cd /var/lib/apt michael@Ubuntu:/var/lib/apt$ sudo mv lists lists.old michael@Ubuntu:/var/lib/apt$ sudo mkdir -p lists/partial michael@Ubuntu:/var/lib/apt$ sudo apt-get clean michael@Ubuntu:/var/lib/apt$ sudo apt-get update E: The method driver /usr/lib/apt/methods/https could not be found. E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it? michael@Ubuntu:/var/lib/apt$ sudo apt-get update E: The method driver /usr/lib/apt/methods/https could not be found.   Why am I getting these errors when doing an apt-get update?
There are many cases in maths where doing the same thing over and over again will bring you closer to a value. Derivation of polynomials is the striking example: no matter what you start with, you end up with 0. In a series expansion, the longer you continue the sequence the closer you get to the real value.  This concept applies in areas other than math (Wikipedia's everything-leads-to-philosophy phenomenon, for example). It's a little unrelated but it just proves the concept.  Hashing algorithms are just special math. Following logically, hash entropy supposedly decreases the more you hash a value. So is there a point at which any input value will give the same hash as any other?  (Let me just specify that we're not re-injecting any new data every time we hash, as if we're trying to increase the security of the hash by salting and re-hashing. It's strictly a matter of md5(md5(md5(... if that's the algorithm we're using.  I can see some problems with this already. Algorithms like md5 are designed to change their output radically when the input changes only by one bit of information. So even if a common hash for two values appears along the way, it itself will start changing. But then, does the fact that the output appears to be very different actually mean the possibilities are still many? Background  I am a first year calculus student so I would prefer if answers remained in Layman's terms.  It is common knowledge and seems to me a mantra that I keep hearing over and over again to "not treat differentials/derivatives as fractions".  I am of course, in particular, referring to Leibniz notation.  However, aside from a quick response such as "oh, it's because its not a fraction but rather a type of operator", I never really got a full answer as to why we can't treat it as such. It just kind of sits at the edge of taboo in my mind where it sometimes gets used and sometimes doesn't.  Confusion is further compounded when a lot of things seem to just work out if we treat them just as fractions (e.g. u-substitution / related-rates)    Example     Air is being pumped into a balloon at a rate of $100cm^3/s$. We want the rate of change of radius when the radius is at $25cm$.   $$\text{we are given}\ \frac{dv}{dt}=100cm^3/s$$ $$\text{we want}\ \frac{dr}{dt}\ \text{when}\ r=25cm$$ Thus we will solve this by using the relation $v=\frac{4}{3}\pi r^3$ $$\frac{dv}{dt}=\frac{dv}{dr}\frac{dr}{dt}$$ $$\frac{dv}{dt}\frac{dr}{dv}=\frac{dr}{dt}$$ $$100\frac{1}{4\pi r^2}=\frac{1}{25\pi}$$ So the answer is $\frac{dr}{dt}=\frac{1}{25\pi}$ when $r=25cm$  *Note the manipulation of derivatives just as if they were common fractions using algebra.    Question  When exactly can I treat differentials/derivatives as fractions and when can I not?   Please keep in mind that at the end of the day, I am a first year college student. An answer that is easy to understand is preferred over one that is more mathematically rigorous but less friendly to a beginner such as me. What's the difference between an inverter with a bubble at the input and one with a bubble at the output? See , page 2: the internal logic diagram for the MM74HC138.    The diagram shows logic inverters with bubbles at the input or at the output. Is there an actual difference between them? Possible Duplicate:          In  the following claim was mentioned:  $R/I \otimes_R M \cong M / IM$  So I tried to prove it. Can you help me finish my proof? Thanks!    We recall that $M \otimes_R -$ is a covariant right-exact functor that it is exact if $M$ is flat and we observe that the following is an exact sequence: $$ 0 \to IM \xrightarrow{i} M \xrightarrow{\pi} M / IM \to 0$$  $R/I$ is an $R$ module since $R/I$ is a subring of $R$ closed with respect to multiplication from $R$ but it is not necessarily flat hence we only get exactness on one side:  $$  (R/I) \otimes_R IM \xrightarrow{id \otimes i} (R/I) \otimes_R M \xrightarrow{id \otimes \pi} (R/I) \otimes_R M / IM \to 0$$  Then $$ \mathrm{Im(id \otimes \pi)} = (R/I) \otimes_R M / IM  \cong (R/I) \otimes_R M / \mathrm{Ker} (id \otimes i) $$  so we want to show two things:   (i) that $\mathrm{Ker} (id \otimes i) = \{0\}$. To this end let $r + I \otimes im \in (R/I) \otimes_R  IM $ and assume $ id \otimes i(r + I \otimes im ) = r + I \otimes im = 0 + I \otimes 0$. I'm not sure how to proceed from here.   (ii) and that $M /IM \cong (R/I) \otimes_R M / IM $  Can you help me? Thanks. Can future execution start before the synchronous execution is completed Is there a way for @future annotated method to start execution before the synchronous request which invokes it has completed.  In other words, do I have some guarantees that the timing will look like this:  -start sync---call future---end sync---execute future-&gt;   instead of like this:  -start sync---call future---execute future---end sync-&gt;   I couldn't find the execution order guarantees in the documentation, although  states:     The reason why sObjects can’t be passed as arguments to future methods   is because the sObject might change between the time you call the   method and the time it executes. In this case, the future method will   get the old sObject values and might overwrite them.  To work with   sObjects that already exist in the database, pass the sObject ID   instead (or collection of IDs) and use the ID to perform a query for   the most up-to-date record.   This can be read as saying that the future is not queued at the end of the transaction, otherwise Salesforce could guarantee that the sObject sent is the most recent version. And since it's queued during the transaction, it might imply that it also might execute and complete while the synchronous transaction is still running.  On the other hand,  implies that futures are only fired after the transaction completes:     Invoking Database.rollback not only rolls back inserts, but it goes   much, much further.   [...]   It also rolls back:      Calls to @future methods. Any methods called within the rolled back part of your script will not be invoked (also why @future doesn't start until your script completes). l, ls & la -- what are the differences, and are there more of these commands? Is $f(x)=10$ a periodic function? I am not getting satisficatory explanation for this. Clearly $f(x+T) = f(x)$ for all values of $T$.  If we assume it is periodic, does this mean period =  $0$? Add Item to Finder Sidebar Solvability of $a \equiv x^2 \mod b$ Is there a way to get the name of the currently executing method in Java? How to typeset asymmetrical confidence level limits / uncertainties? One of my players has a +1 shortbow, and recently found some +1 arrows. If he fires a +1 arrow from a +1 bow, will the bonus to attack and damage be +1, or +2? Given the Python function:  def a_method(arg1, arg2):     pass   How can I extract the number and names of the arguments. I.e., given that I have a reference to func, I want the func.[something] to return ("arg1", "arg2").  The usage scenario for this is that I have a decorator, and I wish to use the method arguments in the same order that they appear for the actual function as a key. I.e., how would the decorator look that printed "a,b" when I call a_method("a", "b")? $\lim_{x \rightarrow \infty} \lim_{n \rightarrow \infty} f_{n}(x) = \lim_{n \rightarrow \infty}\lim_{x \rightarrow \infty}f_{n}(x) $ in case of uniform convergence of $f_{n}(x)$ to $f(x)$  I used this while I was given that $f_{n}(x)$ converges to $f(x)$ uniformly. Is this correct and I was also thinking to prove this! Deleted comments are persisting in the global inbox I realise that there is other questions out there about the  (First open one I found is ), but this is marked .  I often get the below issue where it will notify me about comments on my  (in this case what appears to be the user re-writing after deleting their comment) that no longer exist.  Also, occasionally, I see comment snippets with text that doesn't match what is on the page when I view it.  Let me know if I should be trying to edit that one to remove the tag indicating that it has been fixed, and add the above as another answer. align xticks in PGFPlots The text xticks are not placed on the same line, rather the same height counting from the highest letter (zero is much higher than high and low).    How can you fix this?  MWE:  \documentclass[class=scrartcl,14pt]{standalone} \usepackage{fontspec} \usepackage{luatex85} \usepackage{unicode-math} \usepackage{tikz} \usepackage{pgfplots,pgfplotstable} \usepackage{calc} \usepgfplotslibrary{groupplots} \pgfplotsset{compat=newest}  \begin{document}  \begin{tikzpicture} \begin{groupplot}[group style={group size=1 by 1, horizontal sep=2cm, xlabels at=edge bottom }, %~ yticklabel style={/pgf/number format/fixed}, %~ xticklabel style={/pgf/number format/fixed}, scaled y ticks = false, scaled x ticks = false, xtick pos=left, ytick pos=left, %xlabel=time (week) ] \nextgroupplot[xmin=0.5,xmax=3.5,xtick={1,2,3},ymin=2.43,ymax=3.05,xticklabels={zero, low , high}, xlabel={label}]  \end{groupplot}  \end{tikzpicture}  \end{document} \footnote breaks @-constructs in \index I would like to use Zapf's Palatino font for the text in my document, which also includes a lot of maths. And I would like a good font for the maths. This is a snapshot of what I am doing.  \documentclass[10pt,letterpaper]{memoir} \usepackage{amsmath} \usepackage{amssymb} \usepackage{mathpple} \usepackage{upgreek} \usepackage{mathpazo} \usepackage{lipsum}  \begin{document}  \chapter{Demo}  Some regular text. \lipsum[1]  Now for some maths.  \begin{displaymath} P_{N-1 + m} = \frac{C}{N-{1} + m} \binom{N_{2} - N_{1}}{m}         \alpha^{m}\beta^{(N_{2} - N_{1}) -m} \end{displaymath}  The number 27 is the sum of the first 5 odd prime numbers: $27 = 1+3+5+7+11$  \end{document}   To me the text and math fonts seem a good fit but the text does not look like Palatino. how to set static ip from bash scriptlinux I want to set static IP using bash script what I would to achieve I want to set the same IP to static which is come from DHCP, for example, my eth0 set to DHCP and it picks IP 51.89.84.82 for eth1 it pick 10.0.0.1 I want to set the same IP to static how can I achieve this in centos7. 1 ) find interface name and its ip , subnet mask , gateway. 2 ) loop each interface and set the same ip , subnet and gateway. NullReferenceException in Unity Since many users are facing the NullReferenceException: Object reference not set to an instance of an object error in Unity, I thought that it would be a good idea to gather from multiple source some explanation and ways to fix this error.  Symptoms I am getting the error below appearing in my console, what does it mean and how do I fix it?  NullReferenceException: Object reference not set to an instance of an object