I'm looking for an app or programme that can draw similar to Sketchup
Is there an equivalent to Google Sketchup?
Need help to understand Maximum Likelihood Estimation for multivariate normal distribution? In maximum likelihood estimation for the parameter, mean $\mu$ of multivariate normal distribution, I end up with the following result:  $\mu_{MLE} = \dfrac{1}{n}\sum_{i=1}^n x_i$  The way I understand the above equation is the following way below, but I am wondering if the above equation means the following equation:  $\mu_{MLE} = \begin{bmatrix}\mu_1\\\mu_2\\\vdots\\\mu_n\end{bmatrix} = \begin{bmatrix}\dfrac{1}{n}\sum_{i=1}^n x_1\\\dfrac{1}{n}\sum_{i=1}^n x_2\\\vdots\\\dfrac{1}{n}\sum_{i=1}^n x_i\end{bmatrix} = \begin{bmatrix}E(X_1)\\E(X_2)\\\vdots\\E(X_n)\end{bmatrix} = \begin{bmatrix}\bar{X_1} \\ \bar{X_2} \\ \vdots \\ \bar{X_n}\end{bmatrix}$   And also Maximum Likelhood Estimation for $\Sigma$, I have ended up with the following equation:  $\Sigma_{MLE} = \dfrac{1}{n}\sum_{i=1}^n(x_i-\mu)(x_i-\mu)^T = \begin{bmatrix}Var(\sigma_{11}) &amp; Cov(\sigma_{12}) &amp; \dots &amp; Cov(\sigma_{1n}) \\ Cov(\sigma_{21}) &amp; Var(\sigma_{22}) &amp; \dots &amp; Cov(\sigma_{2n}) \\ {}&amp; \vdots&amp;  \\ Cov(\sigma_{n1}) &amp; Cov(\sigma_{n2}) &amp; \dots &amp; Var(\sigma_{nn})  \end{bmatrix}$  Somehow, I got the equation following some algebraic steps, but I can't see how this part, $\dfrac{1}{n}\sum_{i=1}^n(x_i-\mu)(x_i-\mu)^T$, works and produces the covariance matrix. Hope to hear some explanations. SSH welcome message on 17.04 shows notice about 12.04 I just did a do-release-upgrade going from Ubuntu 16.04 to 17.04. However, now when I login via SSH I have the following message   Welcome to Ubuntu 17.04 (GNU/Linux 4.10.0-20-generic x86_64)   * Documentation:  https://help.ubuntu.com  * Management:     https://landscape.canonical.com  * Support:        https://ubuntu.com/advantage  Ubuntu 12.04 LTS end-of-life was April 28, 2017 -- Upgrade your Precise systems!  $ sudo do-release-upgrade -m server  0 packages can be updated. 0 updates are security updates.   My question is, how can I remove the   Ubuntu 12.04 LTS end-of-life was April 28, 2017 -- Upgrade your Precise systems!  $ sudo do-release-upgrade -m server   it wasn't there prior the release-upgrade  I checked and I am on Zesty  lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 17.04 Release:    17.04 Codename:   zesty   My question is not, how can I remove this message, this I found. My question is more, is there a reason why this appears after a release-upgrade? Is this message something generic not taking into consideration the current version of Ubuntu? Or maybe my system is not updated properly? Intersection of powers of an ideal in a Noetherian ring Given a Noetherian ring $R$ and a proper ideal $I$ of it.  Is it true that $$\bigcap_{n\ge 1} I^n=0$$ as $n$ varies over all natural numbers? If not, is it true if $I$ is a maximal ideal? If not, is it true if $I$ is the maximal ideal of a local ring $R$? If not, is it true under additional assumptions on $R$ (like $R$ is regular)? Asking the position of a person in a sequence How can a piece of A4 paper be folded in exactly three equal parts? This is something that always annoys me when putting an A4 letter in a oblong envelope: one has to estimate where to put the creases when folding the letter. I normally start from the bottom and on eye estimate where to fold. Then I turn the letter over and fold bottom to top. Most of the time ending up with three different areas. There must be a way to do this exactly, without using any tools (ruler, etc.). SQL Server, convert a named instance to default instance? I need to convert a named instance of SQL server 2005, to a default instance.  Is there a way to do this without a reinstall?    The problem is, 2 out of 6 of the developers, installed with a named instance. So its becoming a pain changing connection strings for the other 4 of us. I am looking for the path of least resistance to getting these 2 back on to our teams standard setup.    Each has expressed that this is going to be, too much trouble and that it will take away from their development time. I assumed that it would take some time to resolve, in the best interest of all involved, I tried combing through configuration apps installed and didn't see anything, so I figured someone with more knowledge of the inner workings would be here. I am getting several new computers for my office.  I want to install Microsoft Office and my proprietary software and all updates on a single PC and create a system image that will be copied to every other PC.  How do I deal with Windows/Office product keys to prevent licence violations?  Am I able to do this from the System Image tool in Windows 7?  Note:  The PCs will very likely not be joined to my domain at this point if that makes a difference. Why does no one notice the Joker's presence as a policeman during the mayor's speech? Explanation for "emails"? Planet where humans fight for access to algae It's time for drag and drop! I often find myself wishing SO supported drag and drop. For example I drag a tag to my favs and it would add it, or when searching by tag I would like to drag the tag to the search box and get [asp.net] added in the search box.   Does it make sense to add this feature or is it just too much work for so little use? How to add right-click (on desktop) to create text file functionality 16.04.2 Ubuntu GNOME sum pair of columns based on matching fields Installing MinionPro fonts on Ubuntu 10.04 running TexLive 2012 I followed the instructions to install MinionPro fonts from this website.   However, when I tried to run the tex file at the bottom, I have this error message:  ! LaTeX Error: File `MinionPro.sty' not found.   Running the command kpsewhich MinionPro.sty gives the following output:  /usr/local/share/texmf/tex/latex/MinionPro/MinionPro.sty   So the system knows where MinionPro.sty is, so why can't the file compile? Can I use Beetel 450TC1 as wireless router? Cannot add custom launcher to Ubuntu Dock ('Add to Favorites' option does not show up) I have a custom .desktop file: [Desktop Entry] Type=Application Terminal=false Icon[en_US]=/home/alex/bin/idea-IC-173.4127.27/bin/idea.png Name[en_US]=IntelliJ Exec=/home/alex/bin/idea-IC-173.4127.27/bin/idea.sh Name=IntelliJ Icon=/home/alex/bin/idea-IC-173.4127.27/bin/idea.png  Output of ls -lha .local/share/applications/intellij.desktop: -rwx--x--x 1 alex alex 248 Dez 30 10:54 .local/share/applications/intellij.desktop  Answers posted to a previous question () don't work for me. I can find this launcher in Activities and I can double click on that file and IntelliJ will start. Nevertheless, I cannot add this launcher as a favorite to the dock. The option does not show up. I know $[0,1]$ denotes the interval between 0 and 1 with the boundary. And $(0,1)$ denotes the interval between 0 and 1 without the boundary. Today, I encounter some expressions as $]0,1]$, $]-\infty,+\infty]$. What does $]0,1]$ mean? Thanks. Function whose inverse is also its derivative? What are some good examples of a function  $f : \mathbb{R} \to \mathbb{R}$ where its derivative is equal to its inverse? I attempted to find a monomial that satisfied it by starting with $f(x) = ax^b$ and showing that $f^{-1}(x) = f'(x) \implies b-1=\frac{1}{b} \implies b=\phi$ and got $$f(x) = \frac{x^\phi}{\sqrt[\phi]{\phi}}$$ Which seems to work according to WolframAlpha, but I'm having trouble double-checking it. Any other ideas? I noticed there is a square knob sticking out of my basement wall. Does anyone know what this is? I am attempting to settle a friendly bet.  Would a pendulum swing indefinitely in a hypothetical vacuum (i.e. no air resistance) having a hypothetical frictionless bearing (i.e. no energy lost due to friction) assuming the following   The frictionless vacuum is on Earth (9.8 m/s^2). The pendulum is already in motion and no other external forces other than gravity act on the pendulum.