Looking at the site with older versions of Ubuntu it seems like 64bit on amd chips is the only option. I can upgrade the ram but I am pretty sure I am stuck with a 32bit processor. This PC had Windows XP installed but cannot reach the update site. Just want to try installing ubuntu or some other linux to see if there is some hardware malfunction.
For a given hardware configuration, how do I find out if Ubuntu will run on it? What considerations should I take into account when choosing an Ubuntu version and  such as:    with a lighter desktop than the usual Gnome and Unity  with the even lighter LXDE desktop   Obviously Ubuntu does not run on some processor architectures. So how do I go about choosing the right version and derivate. How can I find out the minmal system requirements?
Primes congruent to 1 mod 6 I came across a claim that I found interesting, but can't seem to prove for some reason. I have the feeling it should be easy  a prime $p$ can be written in the form $p = a^2 -ab +b^2$ for some $a,b\in\mathbb{Z}$ if and only if $p\equiv 1\bmod{6}$ Can I insert elements to the beginning of an element using .appendChild()? If the user selects an option in a dropdown box, there must be added a label and a textbox. Using appendChild, these elements get added to the end of the container.  var newFreeformLabel = document.createElement('label'); newFreeformLabel.innerHTML = 'Omschrijving:';  var newFreeformField = document.createElement('input'); newFreeformField.className = 'textfield'; newFreeformField.name = 'factuur_orderregel[]';  var newFreeformSpacer = document.createElement('div'); newFreeformSpacer.className = 'spacer';  container.appendChild(newFreeformLabel); container.appendChild(newFreeformField); container.appendChild(newFreeformSpacer);   The issue is that these elements should be inserted at the beginning of container, not at the end.  Is there a solution to this in PrototypeJS? Excel How to make Text Qualifier editable or add a new entry in the existing list? Proof that the coefficients in an OLS model follow a t-distribution with (n-k) degrees of freedom Background  Suppose we have an Ordinary Least Squares model where we have $k$ coefficients in our regression model, $$\mathbf{y}=\mathbf{X}\mathbf{\beta} + \mathbf{\epsilon}$$  where $\mathbf{\beta}$ is an $(k\times1)$ vector of coefficients, $\mathbf{X}$ is the design matrix defined by  $$\mathbf{X} = \begin{pmatrix} 1 &amp; x_{11} &amp; x_{12} &amp; \dots &amp; x_{1\;(k-1)} \\ 1 &amp; x_{21} &amp; \dots  &amp;       &amp;   \vdots \\ \vdots &amp;   &amp; \ddots &amp;       &amp;   \vdots \\ 1 &amp; x_{n1} &amp; \dots  &amp; \dots &amp;   x_{n\;(k-1)}     \end{pmatrix}$$ and the errors are IID normal,  $$\mathbf{\epsilon} \sim \mathcal{N}\left(\mathbf{0},\sigma^2 \mathbf{I}\right) \;.$$  We minimize the sum-of-squared-errors by setting our estimates for $\mathbf{\beta}$ to be $$\mathbf{\hat{\beta}}= (\mathbf{X^T X})^{-1}\mathbf{X}^T \mathbf{y}\;. $$   An unbiased estimator of $\sigma^2$ is  $$s^2 = \frac{\left\Vert \mathbf{y}-\mathbf{\hat{y}}\right\Vert ^2}{n-p}$$ where $\mathbf{\hat{y}} \equiv \mathbf{X} \mathbf{\hat{\beta}}$ ().   The covariance of $\mathbf{\hat{\beta}}$ is given by $$\operatorname{Cov}\left(\mathbf{\hat{\beta}}\right) = \sigma^2 \mathbf{C}$$ where $\mathbf{C}\equiv(\mathbf{X}^T\mathbf{X})^{-1}$ () .  Question  How can I prove that for $\hat\beta_i$, $$\frac{\hat{\beta}_i - \beta_i} {s_{\hat{\beta}_i}} \sim t_{n-k}$$ where $t_{n-k}$ is a t-distribution with $(n-k)$ degrees of freedom, and the standard error of $\hat{\beta}_i$ is estimated by $s_{\hat{\beta}_i} = s\sqrt{c_{ii}}$.    My attempts  I know that for $n$ random variables sampled from $x\sim\mathcal{N}\left(\mu, \sigma^2\right)$, you can show that  $$\frac{\bar{x}-\mu}{s/\sqrt{n}} \sim t_{n-1} $$ by rewriting the LHS as $$\frac{ \left(\frac{\bar x - \mu}{\sigma/\sqrt{n}}\right)  }   {\sqrt{s^2/\sigma^2}}$$ and realizing that the numertor is a standard normal distribution, and the denominator is square root of a Chi-square distribution with df=(n-1) and divided by (n-1) ().  And therefore it follows a t-distribution with df=(n-1) ().  I was unable to extend this proof to my question...  Any ideas?  I'm aware of , but they don't explicitly prove it, they just give a rule of thumb, saying "each predictor costs you a degree of freedom". How to install a Brother dcp-135c printer? Recently moved over onto Ubuntu. First time for anything like this for me as I'm coming from Windows but I'm here and ready to learn. The only problems Ive experienced so are saving in Libre office doc as a word doc file and then losing the formatting upon receival via email. However the more pressing issue is getting my old Brother DCP 135 c to work. Ive scanned a few help blogs and have found them frankly quite frightening.  Would it be possible for someone to write u a step by step guide (including explanations of terminology)  For those of us new to this magic world? Short story: rocket fuel which oxidizes iron destroys life on earth I'm looking for the title of a short science fiction story, probably published in a Hugo winner collection 30 years ago. In the story, scientists have developed an extremely efficient rocket fuel that has one dangerous side-effect: it oxidizes iron. A man takes off in a rocket powered by this fuel but returns to find the earth completely devoid of life. His subsequent investigation reveals that a single drop of the fuel began a domino effect, as the substance oxidized all iron it came into contact with. In the end, the man is dying.  He drags himself to the ocean, believing that if he can get his living cells into the water they will restart the primordial soup. My question was closed for being a "shopping list question", even though it was very much related to the topic of the site. Why? I am trying to write code with rotates an object.  I implemented it as:  Rotation about X-axis is given by the amount of change in y coordinates of a mouse and  Rotation about Y-axis is given by the amount of change in x coordinates of a mouse.  This method is simple and work fine until on the the axis coincides with Z-axis, in short a gimble lock occurs.  How can I utilize the rotation arount Z-axis to avoid gimbal lock. Waiting for user input with a timeout I have searched but apparently my google foo is weak. What I need is a way to prompt for user input in the console and have the request time out after a period of time and continue executing the script if no input comes in. As near as I can tell, Read-Host does not provide this functionality. Neither does $host.UI.PromptForChoice() nor does $host.UI.RawUI.ReadKey(). Thanks in advance for any pointers.  EDIT: Much thanks to Lars Truijens for finding the answer. I have taken the code that he pointed out and encapsulated it into a function. Note that the way that I have implemented it means there could be up to one second of delay between when the user hits a key and when script execution continues.  function Pause-Host {     param(             $Delay = 1          )     $counter = 0;     While(!$host.UI.RawUI.KeyAvailable -and ($counter++ -lt $Delay))     {         [Threading.Thread]::Sleep(1000)     } } Noun-adjective reversal - was it ever in use in plain speech? Peltier Unit Not Working How does the telepathy supernatural ability work? According to the MM books, telepathy is described as:     A creature with this ability (supernatural) can communicate telepathically with any other creature within a certain range (specified in the creature's entry, usually 100 feet) that has a language. It is possible to address multiple creatures at once telepathically, although maintaining a telepathic conversation with more than one creature at a time is just as difficult as simultaneously speaking and listening to multiple people at the same time.   Source: MM, MM3   My questions:   If a creature with telepathy knows that someone is within 100ft, can the creature communicate with that person, even if there is no line of effect or sight?  My answer would be yes, because no book says that telepathy is blocked by walls, etc. Normally, a supernatural ability is a standard action to start. If the creature wanted to communicate for more than one round using telepathy, does the creature need to use up a standard action every round they are communicating or only in the first round?  My answer is only in the first round, since the description says that maintaining telepathy is hard as speaking and listening normally. If a person the creature is communicating with moves out of the 100ft range, and then moves back into the range. Does the telepathic link need to be established again?  My answer is yes, another standard action is needed to establish the telepathy between the two creatures.   I should add the telepathy is supernatural, and a character is looking at getting it from the Mindbender class (from Complete Arcane). And also get the Mindsight feat (Lords of Madness). I couldn't find anywhere to rule whether a supernatural ability should take a standard action every round it is on. How to revert to GNOME Classic Desktop? options for [for /f "usebackq" %%f in (`find "" path`) do] sentence in batch I symplified my problem: @echo off set res=  for /f &quot;usebackq&quot; %%f in (`find &quot;a&quot; list.txt`) do set res=%%f echo %res%  pause&gt;nul and that things.txt file in the code is like:  list.txt file in the code is: apple pitch pear melon mango  As you expect, the result of this code is mango  because the line 'mango' is located below the line 'apple' and 'pear' But the result I want is apple  or pear  Specifically, I want to put each of the other values above mango such as apple and pear into the variable res using option keys provided. is there any way to do that? Just noticed the "meta user" link under the picture and reputation on the Stack Exchange user's page. It doesn't seem to work for all users. Error is "Page Not Found".   Not working:  /  Working:  /    My guess is this is because they've never logged into the meta site. I would like to prove the following equality: $$k^{\phi(l)} + l^{\phi(k)} \equiv1\pmod{lk}$$if $\gcd(l,k)=1$. What methods can I use? Thank you for your help. 'sudo su -' vs 'sudo -i' vs 'sudo /bin/bash' - when does it matter which is used, or does it matter at all? How can I calculate magnification ratio I get by reversing a lens? I am looking for a way to mathematically determine the maximum magnification ratio that is possible/practical to achieve by reverse mounting a non-macro lens, prior to purchasing the lens.     See related questions: I recently read that:     What our current level of thermodynamics does tell us though is that if there is such a thing as a Big Crunch, the universe will look a lot different as it heads towards collapse than it did when expanding – the universe started in a state of low entropy and high order and will end in a state of high entropy and   low order.   But shouldn't the order be in a high state and hence entropy becomes a low state in the Big Crunch (assuming a closed universe)?  The reason I write this is because the gravitational forces in a closed universe are so strong they will cause gravitational collapse so the universe will shrink and go backwards, eventually through all the stages of the big bang and become a singularity once more.   It was my understanding that a singularity has a state of high order and low entropy. Have I got this the wrong way round?   If so; Can someone please explain why? $AB-BA$ is a nilpotent matrix if it commutes with $A$ I saw this in a  and am putting it here for posterity.  Problem: Let $A$ and $B$ by square matrices and set $C=AB-BA$. If $AC=CA$, prove $C$ is nilpotent.