So I have ran into some trouble installing g++. When I try to use the &quot;sudo apt install g++&quot;, command it asks me if I really want to install it, and when I say yes, it just leaves me this message: &quot;Insert the „Ubuntu 20.04.2 LTS Focal Fossa - Release amd64 (20210204)” called CD to the /cdrom/ drive and press enter&quot; (Or something like that, I tried to translate it from Hungarian) I give you an image of my problem, however my Ubuntu is in Hungarian, so i don't think that it would be useful. Here it is:  I have already tried to get the .iso file and just mount it to my cd drive, but it didn't solve the problem. Should I just reinstall Ubuntu or what should I do?
I can't update 12.04 LTS. The Update Manager shows this:  CD/DVD 'Ubuntu 12.04 LTS _Precise Pangolin_ - Release i386 (20120423)' is required Please insert the above CD/DVD into the drive '/media/cdrom/' to install software packages from it.   The image I downloaded and burned to CD is from  the PC (Intel x86) desktop CD version. I burned many CDs but the result is the same.
What did Auggie's father give to his wife in the movie Wonder? There is a scene roughly in the last third of Wonder where Auggie's parents Nate and Isabel (Owen Wilson and Julia Roberts) spend an evening together while the kids are out. Nate has a surprise gift for his wife. She opens the box just enough to see it, laughs, and closes it again. So I asked myself the question:  What's in the box? How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$? If $f:D\to D’$ is analytic and $u: D'\to R$ is harmonic then the composition of $u$ and $f$ is harmonic in $D$ If $f:D\to D’$ is analytic and $u: D'\to R$ is harmonic then the composition of $u$ and $f$ is harmonic in $D$.  How can I show that the above statement is true/false? Can anyone help me? Lets say we have a dependent variable $Y$ with few categories and set of independent variables.    What are the advantages of multinomial logistic regression over set of binary logistic regressions (i.e. )? By set of binary logistic regression I mean that for each category $y_{i} \in Y$ we build separate binary logistic regression model with target=1 when $Y=y_{i}$ and 0 otherwise. Is the use of "one of the" correct in the following context? Question: If $c\neq 1$ is an $n^{th}$ root of unity then, $1+c+...+c^{n-1} = 0$  Attempt: So I have established that I need to show that $$\sum^{n-1}_{k=0} e^{\frac{i2k\pi}{n}}=\frac{1-e^{\frac{ik2\pi}{n}}}{1-e^{\frac{i2\pi}{n}}} =0$$ by use of the sum of geometric series'. My issue is proceeding further to show that this is indeed true. Formatting a bootable USB that thinks it's a CD-ROM After upgrading to Windows 10, I remember that I had an old bootable recovery usb drive from the manufacturer that I no longer needed. I want to format it but it's showing up as a CD-ROM and format options are not available.  I also tried formatting it in a live linux mint environment, but linux cannot even mount the cd-rom.  How can I format this recovery usb that is showing up as a cd-rom? Can't understand a proof: Let $a,b,c$ be integers. If $a$ and $b$ divide $c$, then $lcm(a,b)$ also divides $c$  Proof I've been shown:  Since $c$ is a common multiple of $a,b$, it means that $lcm(a,b) \leq c$.  So: $c=q\cdot lcm(a,b)+r$, $q \in \mathbb Z$ and $0\leq r \leq lcm(a,b)$  Since $c$ and $lcm(a,b)$ are common multiples of $a,b$, then so is $r$. But $m$ is the least common divisor, then it means $r=0$.   [Proof taken from: http://www.math.utah.edu/~wood/4400/hw1sol.pdf]  I cannot understand the last step... Why does it imply that $r=0$?   Thank you! How can I show that "A center of a free group that is non-cyclic is trivial" ? What's the best way to use matching methods with multiple treatment groups? I'm assessing the impact of an intervention on an outcome. For my first analysis, I used the MatchIt package (see code below) to match treatment and control groups and to compare outcomes for the treated vs control. The Treat variable is 0 or 1.  nn_match &lt;- matchit(treat ~ cov1 + cov2+ cov3 ,                      method = "nearest", data = df)   In my second analysis, I'd like to assess the effect of different treatment levels (for example, I have Treatment A, Treatment B, and Treatment C) on the outcome, but I'm stuck on the best way to proceed. Does it make sense to run separate matching analysis for each treatment group while excluding the observations from the other treatments groups?   nn_treatA_match &lt;- matchit(treat_A ~ cov1 + cov2+ cov3 ,                      method = "nearest", data = df_minus_other_treatBC) nn_treatB_match &lt;- matchit(treat_B ~ cov1 + cov2+ cov3 ,                      method = "nearest", data = df_minus_other_treatAC)   Or is there a way to run the analysis with the entire dataset and match controls to each treatment at the same time? Other posts have mentioned the twang package, but I'm not sure if that's what I should go with as I'd like to compare outcomes for each treated group to the control and not just across treated groups. Whoever or whomever: 'happy for ___ has the pleasure of working with you next.' So sad to lose you, yet happy for whomever has the pleasure of working with you next. I want to copy a live production database into my local development database.  Is there a way to do this without locking the production database?  I'm currently using:  mysqldump -u root --password=xxx -h xxx my_db1 | mysql -u root --password=xxx -h localhost my_db1   But it's locking each table as it runs. d'Alembert-like functional equation: $f(x+y)+g(x-y)=\lambda f(x)g(y)$ Why do ssh operations always ask for passphrase? (with ed25519) I just updated my ssh key and added a passphrase, however it constantly nags me for it now, such as when I do a git (or mercurial hg) push.  ssh-agent is running:  xxx  1303  1118  0 09:16 ?  00:00:00 /usr/bin/ssh-agent    /usr/bin/dbus-launch --exit-with-session     /usr/bin/im-launch mate-session   I tried ssh-add:  &gt; ssh-add Identity added: /home/…/.ssh/id_rsa (/home/…/.ssh/id_rsa) Enter passphrase for /home/…/.ssh/id_ed25519:  Could not add identity "/home/…/.ssh/id_ed25519":      communication with agent failed   What is missing?  16.04 Ubuntu Mate, in case it matters. SSH access to office host behind NAT router I would like to access the ssh port of my office linux host from home. Unfortunately the host is located behind a NAT router. So, the IP address is not publicly available. There is however access to another internet host (Server) which is unfortunately only non-root access. After a while of searching I do not find a suitable solution.  Following setup:   Office PC (linux, root access) behind NAT (IP not public) but full Internet access. Server PC (linux, no root access) static and public IP and full Internet access. Home PC (linux, root access) behind NAT (IP not public) but full Internet access.   Possible connections: Office PC --> Server &lt;-- Home PC  Not possible: Office PC &lt;-X- Server -X-> Home PC  Neither the Home PC, nor the Server can initiate access to the Office PC. But both the Office PC and the Home PC can initiate connections to the Server.  Reverse SSH tunnel not possible: I tried a method called reverse ssh-tunnel. Unfortunately this requires GatewayPorts on Server set to "yes" in /etc/ssh/sshd_config, where I have no root access.  In principle it should be possible:   0) On the Server I start a userspace program which listens on 2 ports (1 incoming, 1 outgoing)  1) On my office PC I run a another program which keeps a TCP connection open to the outgoing port on the server.  2) From home I connect to Server's incoming port.  There should be a standard solution for this out there.  What is the quickest and cleanest solution to solve this?  Frank How to get multiple selected values of select box in php? Use of 'const' for function parameters How far do you go with const?  Do you just make functions const when necessary or do you go the whole hog and use it everywhere?  For example, imagine a simple mutator that takes a single boolean parameter:  void SetValue(const bool b) { my_val_ = b; }   Is that const actually useful?  Personally I opt to use it extensively, including parameters, but in this case I wonder if it's worthwhile?  I was also surprised to learn that you can omit const from parameters in a function declaration but can include it in the function definition, e.g.:  .h file  void func(int n, long l);   .cpp file  void func(const int n, const long l)   Is there a reason for this? It seems a little unusual to me. How can I install a package without root access? I have no root access on this machine.  I would like to know if there is a way I can download Ubuntu packages and install them as non-root?  Probably in my ~/bin or ~/usr/share or something like that? Would that work? How long does the Truffle take to move in after building the mushroom biome? I currently find myself in a pickle because even after I've built the mushroom biome and met all other requirements, the Truffle NPC won't move in.   I've defeated not only the Wall of Flesh but Ocram already. Created a surface mushroom biome. Built a house made out of mushrooms with mushroom furniture.   I have no idea how long it takes for the NPC to move in or if I'm wrong in any of the steps. When to use 'by' instead of 'at' or 'on' to specify time/date?