Upon installation of Ubuntu 18.04, I installed the WiFi drivers as per standard procedure from the "Software and Updates" interface and everything was working fine. All of a sudden, without any system update or anything of that sort I was unable to connect to the WiFi because of No WiFi adapter found (despite me having installed it already).  The WiFi is correctly switched on, everything seems to be in place: for instance  $ nmcli radio wifi enabled   and   $ ifconfig enp3s0f2: flags=4099&lt;UP,BROADCAST,MULTICAST&gt;  mtu 1500         ether 30:65:ec:07:51:a7  txqueuelen 1000  (Ethernet)         RX packets 0  bytes 0 (0.0 B)         RX errors 0  dropped 0  overruns 0  frame 0         TX packets 0  bytes 0 (0.0 B)         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0  enx048705ea6058: flags=4163&lt;UP,BROADCAST,RUNNING,MULTICAST&gt;  mtu 1500         inet 192.168.0.224  netmask 255.255.255.0  broadcast 192.168.0.255         inet6 2a02:8109:9200:23cc:306f:334c:5f32:6f5f  prefixlen 64  scopeid 0x0&lt;global&gt;         inet6 2a02:8109:9200:23cc:c419:c684:822a:e929  prefixlen 64  scopeid 0x0&lt;global&gt;         inet6 fe80::83a1:2bfa:d8b2:7313  prefixlen 64  scopeid 0x20&lt;link&gt;         ether 04:87:05:ea:60:58  txqueuelen 1000  (Ethernet)         RX packets 4290  bytes 2741868 (2.7 MB)         RX errors 0  dropped 0  overruns 0  frame 0         TX packets 4149  bytes 564683 (564.6 KB)         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0  lo: flags=73&lt;UP,LOOPBACK,RUNNING&gt;  mtu 65536         inet 127.0.0.1  netmask 255.0.0.0         inet6 ::1  prefixlen 128  scopeid 0x10&lt;host&gt;         loop  txqueuelen 1000  (Local Loopback)         RX packets 873  bytes 70852 (70.8 KB)         RX errors 0  dropped 0  overruns 0  frame 0         TX packets 873  bytes 70852 (70.8 KB)         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0   EDIT: Additional information resulting from wget -N -t 5 -T 10 https://github.com/UbuntuForums/wireless-info/raw/master/wireless-info &amp;&amp; chmod +x wireless-info &amp;&amp; ./wireless-info, as suggested in the comment below, can be found   What can be the cause of the problem? How come, all of a sudden, the drivers seem not to be recognised anymore?
I'm having serious problems installing the Broadcom drivers for Ubuntu. It worked perfectly on my previous version, but now, it is impossible.   What are the steps to install Broadcom wireless drivers for a BCM43xx card?  I'm a user with no advance knowledge in Linux, so I would need clear explanations on how to make, compile, etc.    lspci -vnn | grep Network showed:   Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b]      iwconfig showed:  lo        no wireless extensions. eth0      no wireless extensions.   NOTE: Answer below is updated every time new information is added and confirmed working.
A fiber bundle over Euclidean space is trivial. PHP: Static and non Static functions and Objects In Photoshop I've taken Magic Wand as far as I can, I think. Now I'm left with this grayish edge around the coffee saucer. How do I remove it? I've tried altering tolerance in Magic Wand but don't seem able to get it. Any suggestions please? Can somebody explain "leveraged debt investment positions" and "exposures" in this context for me, please? "The strong bond performance has led to a surge in leveraged debt investment positions that are ultimately funded by the banks' interbank exposures and WMPs. But nobody really knows how levered these positions are, who has financed them, and by how much," S&amp;P said. "The contagion risks for the financial sector could be high."  source: Intuition behind the Definition of Conditional Probability (for 2 Events) Allow converting comments to answers What do you call a person who does/thinks the opposite of the crowd for just that reason? How to make sure an application keeps running on Linux I'm trying to ensure a script remains running on a development server. It collates stats and provides a web service so it's supposed to persist, yet a few times a day, it dies off for unknown reasons. When we notice we just launch it again, but it's a pain in the rear and some users don't have permission (or the knowhow) to launch it up.  The programmer in me wants to spend a few hours getting to the bottom of the problem but the busy person in me thinks there must be an easy way to detect if an app is not running, and launch it again.  I know I could cron-script ps through grep:  ps -A | grep appname   But again, that's another hour of my life wasted on doing something that must already exist... Is there not a pre-made app that I can pass an executable (optionally with arguments) and that will keep a process running indefinitely?  In case it makes any difference, it's Ubuntu. Is it correct that "etc." can not be used together in a sentence with "for example" and "such as"? I just read an article from a Chinese website for English teaching which mentions  that point. For instance, one can't say:     "I can play quite a few musical instruments, for example, the flute, the guitar, the piano, etc.".    The correct one should be:     "I can play quite a few musical instruments, for example, the flute, the guitar, and the piano."    Is it possible to find any references to prove that? Include the option to flag posts as spam in the Low Quality queue I guess this is an additional to previous requests like  and .  But I just came across  review item, and was unable to flag it as spam.  edit: Since I posted this, the item has been removed (deleted) here is a screenshot: AC: Why differentiate between Ground and Neutral? Current flows through a conductor connecting points at different potentials.  Leaving aside multi-phase details, common/conventional AC systems use a 3-wire setup:   Wire-1: a line/live/hot/phase wire presenting a point that oscillates between 2 potentials. Wire-2: a neutral wire presenting a point of unknown/unspecified and varying potential, that nevertheless presents some fixed/specified potential difference to Wire-1 at least some of the time. Wire-3: a ground/earth wire presenting a point at 0V potential difference to its immediate physical surroundings.   Wire-1 and Wire-2, in addition to some device that is to be powered, are used to construct a closed electrical circuit. Wire-3, leaving aside EMI/shielding concerns, is used to ensure that current will flow through it, rather than the device's user, if there ever occur any faults and the device's user comes in contact with Wire-1 or Wire-2.  Additionally to this however, Wire-2 and Wire-3 are at some point connected. This is done to ensure that Wire-2's potential remains close to that of Wire-3 .. which seems to be important for some reason.  Now the part I don't understand is why there needs to be a distinction between Wire-2 and Wire-3 at the power socket, if there is none a few meters further down the line.  I have tried to look this up, but all answers I could find so far seem incomplete. The answers depend on how the question is phrased:   If the question is phrased as "Why do we need Wire-3 in addition to Wire-2" the answer is because "Wire-2 may be at a substantial potential difference to its surroundings/user and thus endanger him/her if he/she ever comes in contact with it or Wire-1". If the question is phrased as "Why do we need Wire-2 in addition to Wire-3" the answer is because "Wire-2 is needed to form a closed electrical circuit" or phrased somewhat differently "Wire-2 is needed to create a potential difference to Wire-1 and thus for current to flow" .. with the argument further being that when taking practical considerations into account Wire-3 can't provide a reliable/stable potential difference to Wire-1 like Wire-2 can.   This doesn't really answer why there's a need to differentiate between Wire-2/Wire-3 though, considering how    Wire-3 remains Wire-3 and maintains 0V potential difference to its surroundings/user, regardless of whatever else happens around it .. since that is what it's supposed to do, or phrased differently, since that is the reason for Wire-3 being useful in the first place .. right?   and   Wire-2 is connected to Wire-3   What am I missing here?    Why is it safe to touch Wire-3 but not Wire-2, or why can Wire-3 provide a level of protection that Wire-2 can't?  Why differentiate between Wire-2 and Wire-3 at the power socket but then connect them further down the line? Autocovariance of an ARMA(2,1) process - derivation of analytical model for $\gamma( k)$ How many non congruent trapeziums are possible with the side lengths from {1,3,4,5,6} I need to find number of mutually non  congruent trapeziums with side lengths from {1,3,4,5,6}.   I know for a trapezium with a,c as non parallel sides the condition for my question is that  $$|a-c|&lt;b+d&lt;a+c$$  But i cant apply it to count the cases. Can someone help in how to get the number of cases? Every irreducible polynomial $f$ over a perfect field $F$ is separable.   Can you check my proof? Assume that $f$ is irreducible but inseparable. So we have $f=\sum_i h_ix^i$ and $f^p=\sum_i h_i^px^{ip}$. Now I use Frobenius mapping $\phi (f)=f^p=(\sum_i h_ix^i)^p=\sum_i h_i^px^{ip}$ so it is reducible. Contradiction. Should I also show for char(F)=0? Is there any way to save the order of spaces in Mission Control? Alternative of `route -n` of Linux in Mac How can I see the list of routes and its corresponding gateway in a Mac ? The command in linux is route -n .  For a particular IP address, I am able to get the routes for an particular IP address via route get 10.0.0.0. Can anyone can suggest where I can freely download ArcObjects SDKs for ArcGIS?  I am using version 10.2. When speaking precisely or technically, one would say that "Homo erectus and homo sapiens are two species of hominid" rather than "Homo erectus and homo sapiens are two species of hominids." The hominid here should be singular because we are speaking about instances of a single class ("class" being used here in its broader sense, not in the sense of taxonomic grouping).  Now let's consider more common parallel constructions replacing the word species with other words.      Tide and Wisk are two brands of detergent.       Tide and Wisk are two brands of detergents.      Cats and dogs are two types of pet you can buy at Pets-R-Us.       Cats and dogs are two types of pets you can buy at Pets-R-Us.   I feel that using the singular noun to specify the class is more grammatically correct, but sounds stilted in conversation. Almost everyone I hear making these constructions uses the plural form. What are your thoughts about singular vs. plural here?  Edit  Here's a more extreme example that may help clarify the issue. Consider the following sentence:     It was my first attempt at calming an angry crowd, and I just        stood there while people were hurling all kinds of insults at me.   Here I think the singular insult sounds strange, if not downright wrong.  Further Edit  I just noticed in A Treasury for Word Lovers (Morton S. Freeman, 1983) a section entitled "Types of Errors." This is a book about (American) English usage by an English professor and editor, which purports to be a "practical guide for serious writers and readers." I wish I could say this discovery satisfies the question, but in fact I now feel somewhat farther from the truth, if there is any single "truth" in this matter. But at least I don't have to worry about being wrong when using the plural form of the class in these constructions. Isn't finding the inverse of $a$, that is, $a'$ in $aa'\equiv1\pmod{m}$ equivalent to solving the diophantine equation $aa'-mb=1$, where the unknowns are $a'$ and $b$? I have seem some answers on this site (where the extended Euclidean Algorithm is mentioned mainly) as well as looked up some books but there is no mention of this. Am I going wrong somewhere or is this a correct method of finding modular inverses? Also can't we find the Bézout's coefficients by solving the corresponding diophantine equation instead of using the extended Euclidean Algorithm? Boundary condition with spatial derivative is ignored by NDSolve