Can my laptop run ubuntu 20.04?
Will my device work with Ubuntu?
Limits, find a limit that exist in absolute value but not outside the absolute value. Center of mass in a straight rod I got an assignment to prove that in a straight homogeneous rod, you can always choose a coordinate system in such a way that  $$\int_S x_1 \, dx_1 \, dx_2=0 $$  $$\int_S x_2 \, dx_1 \, dx_2=0 $$  $$\int_S x_1x_2 \, dx_1 \, dx_2=0$$  where $S$ is the cross section of the rod  Now, intuitively, I can understand that the first two expressions basically state that if you find the mass center of the rod, then all you have to do is to put the origin of the coordinate system in the mass center, and the integrals turn out to be zero. What I'm curious about is whether or not this is a good enough of an explanation, and also, a hint on how to obtain the third equality. Add days to JavaScript Date Which is the best workflow to follow when texturing and importing textures from Substance Painter? So, I'm planning to texture a model using Substance Painter and will render it using the Cycles Render Engine. I will be also using the Principle Shader, heavily, to achieve realistic renders. So, which workflow in Substance Painter so that the textures are accurately rendered in Blender? Specular-Glossy? Or should I go with Metalic-Roughness? Fluent and Query Expression — Is there any benefit(s) of one over other? LINQ is one of the greatest improvements to .NET since generics and it saves me tons of time, and lines of code.  However, the fluent syntax seems to come much more natural to me than the query expression syntax.  var title = entries.Where(e =&gt; e.Approved)     .OrderBy(e =&gt; e.Rating).Select(e =&gt; e.Title)     .FirstOrDefault();  var query = (from e in entries              where e.Approved              orderby e.Rating              select e.Title).FirstOrDefault();   Is there any difference between the two or is there any particular benefit of one over other? Field level permissions in Drupal 7 What is the best way to create a piece of content with multiple fields... allowing users to edit the content as a whole yet blocking the ability to edit.  The setup I have is a piece of content that has 3 fields: Body, PDF, SWF... and a "Selector" (List Text) that's tied via dependancy. So the user chooses BODY, PDF or SWF and that's what available to edit and shown on the page when live.  What I want to do is add a PHP field... that's either:     greyed out (unable to edit) if your not admin...   doesn't show up in the Drop Down list... Can't select it if you can't see it Shows up on the drop down, but the field doesn't show up in the editor without permissions.   I hope I'm making sense... I can provide an example if needed. Is B1 visa in perfect condition valid on old damaged passport? I got my US B1 visa last month on my Indian passport. Someone in my family wrote a phone number on one of the blank page of my passport. As my passport is damaged now, can I travel with my current passport to US or I should apply for new passport? Also, will B1 visa be valid on old damaged passport if I get new passport? Eclipse doesn't start on Ubuntu 18.04 invalid conversion from ‘const char*’ to ‘char’ If $A^{2n}=I$, then $A^n=\pm I$ where $A\in M_n(\mathbb{R})$ Let $A\in M_n(\mathbb{R})$be a matrix. Then, if we have $A^{2n}=I$, can we say that $A^n=\pm I$?  I think yes, because the annihilating polynomial is $x^{2n}-1$. Therefore the characteristic polynomial should be one of $x^n-1$ or $x^n+1$. Thus, since the matrix consists of real numbers, therefore, the matrix $A^n=\pm I$. Am I wrong?Thanks beforehand. Proving that $A_n$ is the only proper nontrivial normal subgroup of $S_n$, $n\geq 5$ There is a famous Theorem telling that:  For $n≥5$, $A_n$ is the only proper nontrivial normal subgroup of $S_n$.  For the proof, we firstly start with assuming a subgroup of $S_n$ which $1≠N⊲S_n$. We proceed until at the last part of proof's body, we assume $N∩A_n=\{1\}$. This assumption should be meet a contradiction with normality of $N$ in $S_n$. There; we get $N=\{1,\pi $} in which $\pi$ is an odd permutation of order $2$. Now for meeting desire inconsistency, I have two approaches:  (a) Since every normal subgroup, having two elements, lies in the center of $G$ so, our $N⊆ Z(S_n)=\{1\}$ for $n≥5$ and then $N=\{1\}$.  (b) Clearly, $1≠N$ acting on set $\Omega=\{1,2,...,n\}$ is intransitive wherein $|\Omega|≥5$ and according to the following Proposition $S_n$ would be imprimitive.  Proposition 7.1: If the transitive group $G$ contains an intransitive normal subgroup different from $1$, then $G$ is imprimitive (Finite Permutation Groups by H.Wielandt).  May I ask if the second approach is valid? I am fond of knowing new approach if exists. Thanks. Capturing image from webcam in java? How can I continuously capture images from a webcam?  I want to experiment with object recognition (by maybe using java media framework).   I was thinking of creating two threads  one thread:   Node 1: capture live image Node 2: save image as "1.jpg" Node 3: wait 5 seconds Node 4: repeat...   other thread:   Node 1: wait until image is captured Node 2: using the "1.jpg" get colors from every pixle Node 3: save data in arrays Node 4: repeat... For a while now I've noticed that if I take a cup of hot tea and pour it into two cups and leave it then both cups will cool faster than the single cup.  How is it that nature cools two cups of tea in parallel more quickly? It's still the same amount of tea but it gets cooled quicker if I have two cups. Is it possible to see cp speed and percent copied? I'm having problems when copying large files using nautilus (it gets stuck). I need to copy, using cp. I would like to know if there are any parameters that shows the % copied and also the transfer speed. php execute a background process I need to execute a directory copy upon a user action, but the directories are quite large, so I would like to be able to perform such an action without the user being aware of the time it takes for the copy to complete.  Any suggestions would be much appreciated. Misplaced/Overlapping Navigation Item Text on iOS 10 The bug displayed in the attached screenshot occurs consistently for me while running the developer beta of iOS 10 using v1.5.2 of the Stack Exchange app on an iPhone 6.  I was able to recreate this by simply tapping on any question or answer in my feed with a long title. This doesn't appear to be a bug with iOS 10 itself since I haven't seen it in other apps, but I could be wrong. Rejection of text containing SQL statements OK, I've been having weird problems for the last 1/2 hour trying to  on StackOverflow, and I keep getting this result (on Firefox 3.6)     The connection was reset      The connection to the server was reset while the page was loading.         The site could be temporarily unavailable or too busy. Try again in a few        moments.   If you are unable to load any pages, check your computer's network        connection.   If your computer or network is protected by a firewall or proxy, make sure        that Firefox is permitted to access the Web.      The problem seems to occur when I try to post some code with 'd--- table' in it, where 'd---' is replaced by the word drop.  I cannot post the following 3 lines, in either SO or this site, if they include the well-known SQL statements DROP.  stat.executeUpdate('d--- table if exists people;'); stat.executeUpdate('create table people (name, occupation);'); prep = conn.prepareStatement(...     'insert into people values (?, ?);');   test again:  'dro* table' 'drop ball' drop the table drop fable drop    t*ble droptable   drop a table  The evil words for me are "drop" and "table"... how come you guys can post? :(  edit: Could someone please suggest another online site that is not stackoverflow that is a quick way to try out a POST request of a text field?  UPDATE: Never mind. I don't know what the answer is, but the same problem occurs on Google's website. So it's not stackoverflow. Now to go to my IT Dept... Showing that $\int_0^\infty x^{-x} \mathrm{d}x \leq 2$. Adding multiple jars to classpath on commandline Reading a binary file and using Response.BinaryWrite()