Why colored text is not shown in terminal? Python
How to print colored text to the terminal?
Let $n \geq 1$ be an odd integer. Show that $D_{2n}\cong \mathbb{Z}_2 \times D_n$. Let $n \geq 1$ be an odd integer. Show that $D_{2n}\cong \mathbb{Z}_2 \times D_n$. I define a map $$\phi:D_{2n} \rightarrow \mathbb{Z}_2 \times D_n$$ by $R \mapsto (0,r^{\frac{n+1}{2}})$ and $M \mapsto(1,m)$. Then I am stuck at showing the map is bijective. By the way, do we need to show that $(0,r^{\frac{n+1}{2}})(1,m)(0,r^{\frac{n+1}{2}})^{-1}=(1,m)$ ? If we can prove this, then what can we conclude? Why is this simple Excel calculation not netting Zero? explicit formula for recurrence relation $a_{n+1}=2a_n+\frac{1}{a_n}$ For $n\in\mathbb N$, $$a_{n+1}=2a_n+\frac{1}{a_n},\quad a_1=1. $$ Can any one give an explicit formula for all $a_n$? If such an explicit general formula doesn't exist, please explain it. I've tried to figure out the $n$-iterated function $f^{(n)}$ where $f(x)=2x+1/x$ or even $f(\tan(t))$. But in either cases, I failed.Since the recurrence isn't linear nor homogeneous,the generating function method doesn't apply here. Does a Grapple or Shove count as an attack for the Mobile feat? The  feat enables you to not get opportunity attacks from creatures you try to attack.  Does it still apply if the attack you made was a Grapple or Shove ? How do I check if a list is empty? For example, if passed the following:  a = []   How do I check to see if a is empty? After an AJAX request, sometimes my application may return an empty object, like:  var a = {};   How can I check whether that's the case? Every finite commutative ring with no zero divisors contains a multiplicative identity? Why does every server I try say it can't connect? I just re-purchased Minecraft (because my old profile stopped working so I bought it) after not playing it for a couple of months. I've added a bunch of servers, but almost every one says "can not connect."  I know its not because the server is not 1.7.2, because I checked that they'd update. It will say "server can't connect" after a long time. I don't know if its me or the servers.  My server screen looks like this (notice the one at the bottom – it's still loading!): Newton's third law of motion states that every action has an equal and opposite reaction. That is the reason we do not sink into the earth, because when our weight exerts a force on the earth it also exerts an equal and opposite force on us.  But when we stand on quicksand or on fluids we can sink in. How is this possible? Does it not exert an equal and opposite force on us? Or are Newton's laws different in the case of fluids and substances of low densities? I  and while on other sites I did not get a 'Reputation Notification' to explain that I was given 2 upvotes for my answer - yet if I manually check my Profile here at meta.SE my total Reputation is in agreement with the amount there.  I'm not knowledgeable about the intercommunication between the servers and sites but I would explain it this way: Super User either failed to send or other sites failed to receive the message the I had a reputation update on Super User.  I should have received either two green star trophies (🏆) of 10 reputation each or one of 20; depending on when I returned to one of the Stack Exchange / Stack Overflow / Super User / etc. sites.  Here's a screenshot showing no reputation change notification for Super User:    Here's a screenshot of my Profile over at Super User showing that I was silently credited:    I'm bringing this up on Meta.SE in case the communication is broken between more sites than just Super User and everywhere else. Should you use a plural verb if you refer to a fraction? apt-get stuck at 0 [Connecting to us.archive.ubuntu.com] When I do upgrade it gets stuck here:  user@plato:~# sudo apt-get upgrade Reading package lists... Done Building dependency tree        Reading state information... Done Calculating upgrade... Done The following packages will be upgraded:   bind9-host coreutils cpio curl dnsutils libbind9-90 libc-bin libc-dev-bin   libc6 libc6-dev libcgmanager0 libcurl3 libcurl3-gnutls libdns100   libdrm-intel1 libdrm-nouveau2 libdrm-radeon1 libdrm2 libisc95 libisccc90   libisccfg90 libjasper1 liblwres90 libplymouth2 libsepol1 libssl-dev   libssl-doc libssl1.0.0 linux-libc-dev mime-support multiarch-support ntp   ntpdate openssl plymouth plymouth-theme-ubuntu-text python3-distupgrade   ubuntu-release-upgrader-core unzip 39 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Need to get 16.0 MB of archives. After this operation, 12.3 kB of additional disk space will be used. Do you want to continue? [Y/n] y 0% [Connecting to us.archive.ubuntu.com (2001:67c:1562::15)] ░   When I do update it gets stuck here:  user@plato:~# apt-get update 0% [Connecting to us.archive.ubuntu.com (2001:67c:1562::14)] [Connecting to sec░   I'm able to ping us.archive.ubuntu.com just fine:  user@plato:~# ping us.archive.ubuntu.com PING us.archive.ubuntu.com (91.189.91.23) 56(84) bytes of data. 64 bytes from economy.canonical.com (91.189.91.23): icmp_seq=1 ttl=54 time=81.5 ms 64 bytes from economy.canonical.com (91.189.91.23): icmp_seq=2 ttl=54 time=81.5 ms 64 bytes from economy.canonical.com (91.189.91.23): icmp_seq=3 ttl=54 time=81.5 ms 64 bytes from economy.canonical.com (91.189.91.23): icmp_seq=4 ttl=54 time=81.4 ms ^C --- us.archive.ubuntu.com ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 3004ms rtt min/avg/max/mdev = 81.425/81.528/81.582/0.355 ms   What can i do to fix this?    What I have tried so far.  I've tried following directions on this blog:   To force apt-get to use IPv4 exclusively   Create a file in /etc/apt/apt.conf.d/99force-ipv4 Add this line to newly created file Acquire::ForceIPv4 false; Apt-get will now use IPv4 exclusively Please help understanding the difference between force and kinetic energy for an object hitting a wall? If a car hits a wall at a speed of $v$, and an identical car hits a wall at a speed of $2\,v$, with the kinetic energy equation $E_K = \frac{1}{2}mv^2$ (the speed goes from $v$ to $0$) the second car will lose 4 times the energy, and therefore cause 4 times the damage, but with the force equation $F = ma$ (the car hits the wall and decelerates), it will hit with 2 times the force, and cause 2 times the damage.  How can this be explained? How to resolve a Java Rounding Double issue How to perform case-insensitive sorting in JavaScript? What would you call a word that doesn't exist in or translate well into another language? Set Path for all Users (Login and Non-login Shells) Ok. So, I'm used to Ubuntu and CentOS more than redhat, so I'm hoping there's some obvious solution to this that I'm missing.  I've installed Anaconda (Python). I've placed it in:  /opt/anaconda3   I would like for myself and all users to be able to have the following in their paths:  /opt/anaconda3/bin   I have googled around and have gained a lot of conflicting information about how to "properly" accomplish my mission.  Stuff I have tried:   Adding a bash script to /etc/profile.d Editing /etc/profile Editing /etc/bashrc Adding to root bashrc Editing user .bashrc   All edits involved some form of:  PATH=/opt/anaconda3/bin:$PATH   or  export PATH=/opt/anaconda3/bin:$PATH   Option 2 yielded the addition of /opt/anaconda3/bin to the path for multiple users, but after terminal restarts still did not run the commands within bin (i.e. conda install, ipython notebook, etc.)  Any ideas? 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