Why not to use "sudo pip install"?
Is `sudo pip install` still a broken practice?
Pullback of a Volume Form Under a Diffeomorphism. I have an exercise here, which I have no idea how to do.     Problem: Let $ U $ and $ V $ be open sets in $ \mathbb{R}^{n} $ and $ f: U \to V $ an orientation-preserving diffeomorphism. Then show that   $$   {f^{*}}(\text{vol}_{V}) = \sqrt{\det \! \left( \left[   \left\langle {\partial_{i} f}(\bullet),{\partial_{j} f}(\bullet) \right\rangle   \right]_{i,j = 1}^{n} \right)} \cdot   \text{vol}_{U}. $$   Notation:         $ \text{vol}_{U} $ and $ \text{vol}_{V} $ denote the volume forms on $ U $ and $ V $ respectively.   $ f^{*}: {\Lambda^{n}}(T^{*} V) \to {\Lambda^{n}}(T^{*} U) $ denotes the pullback operation on differential $ n $-forms corresponding to $ f $. Format string dynamically How do I pack textures for sending off to a render farm Whenever i try to send a project off to a render farm such as sheepit, it says it needs the textures packing with the file in order to render correctly.  How would I do this? Is it possible to modify the title of the message box the confirm() function opens in JavaScript?   I could create a modal popup box, but I would like to do this as minimalistic as possible. I would like to do something like this:  confirm("This is the content of the message box", "Modified title");   The default title in Internet Explorer is "Windows Internet Explorer" and in Firefox it's "[JavaScript-program]." Not very informative. Though I can understand from a browser security stand point that you shouldn't be able to do this. Two column float with [t] using the cas-dc template I am using the cas-dc template for Elsevier. When trying to use \begin{figure*}[t], except I get the error 'The module 'cas/fig' does not have a key called 'cas/fig/t'. Other templates I use work fine. I have included \usepackage{stfloats}. I don't see anything mentioned that strictly forbids it, unless I missed this. Anyone know why? $$\lim\limits_{n\to\infty} \int_{0}^{1} f(x^n)dx = f(0)$$  when f is continuous on $[0,1]$  I know it can be proved using bounded convergence theorem but,  I wanna know proof using only basic properties of riemann integral and fundamental theorem of calculus and MVT for integrals ...   Thank you. Is it possible for reviewers to mistakenly reject a quality paper? unable to use synaptic via launcher When I open synaptic via launcher on gnome-panel, it opens and asks me for the password but if I enter the password, it says its wrong even though the password is correct and it used to work OK few days ago. If I open synaptic via terminal using sudo synaptic then it opens OK without any problem. I have written code like below and all works fine, but while submitting the form I get the error below. I am trying to filter the second dropdown based on the first drop down selection.     An illegal choice has been detected. Please contact the site administrator.   How do I overcome that error?       function dynamic_location_dropdown_form_alter(&amp;$form, $form_state, $form_id) {   if($form_id == 'product_node_form') {    $location_options = array();    if(isset($form['field_destination']['und']['#default_value'][0])) {     $destination = $form['field_destination']['und']['#default_value'][0];   }   else {     $destination = 0;   }    $location_options = dynamic_location_dropdown_locations($destination);    $form['field_destination']['und']['#ajax'] = array(     'event' =&gt; 'change',     'wrapper' =&gt; 'squadron-wrapper',     'callback' =&gt; 'dynamic_location_dropdown_ajax_callback',     'method' =&gt; 'replace',   );   $form['field_product_location']['#validated'] = true;   $form['field_product_location']['und']['#prefix'] = '&lt;div id="squadron-wrapper"&gt;';   $form['field_product_location']['und']['#suffix'] = '&lt;/div&gt;';   $form['field_product_location']['und']['#options'] = $location_options;   } }  function dynamic_location_dropdown_ajax_callback($form, $form_state) {   $country_id = $form['field_destination']['und']['#value'];   $form['field_product_location']['#validated'] = true;   $form['field_product_location']['und']['#options'] =  dynamic_location_dropdown_locations($country_id);    return $form['field_product_location']; }  function dynamic_location_dropdown_locations($destination_id) {   $nodes = array();   $nodes[''] = '- None -';   if($destination_id != '') {     $select = db_query("       SELECT node.title AS node_title, node.nid AS nid, node.created AS node_created       FROM {node} node       LEFT JOIN {field_data_field_location_country} field_data_field_location_country        ON node.nid = field_data_field_location_country.entity_id        AND (field_data_field_location_country.entity_type = 'node'        AND field_data_field_location_country.deleted = '0')       WHERE (( (node.status = '1')        AND (node.type IN  ('location'))        AND (field_data_field_location_country.field_location_country_nid = $destination_id)))       ORDER BY node_title ASC     ");     $nodes[''] = '- None -';     foreach ($select as $node) {       $nodes[$node-&gt;nid] = $node-&gt;node_title;     }   }    return $nodes; } Fake small caps with XeTeX/fontspec? Using XeTeX and fontspec, I use the Liberation font family in of my documents. Unfortunately those fonts (esp. Liberation Serif) do not natively support small caps.  Is there a way to enable fake small caps in fontspec? Can I possibly recover the Windows system partition that I deleted (100MB)? After moving to SSD I deleted the System Partition (100MB) from my previous drive, causing mass destruction.  I tried to delete the System Partition which windows 7 creates (on my previous disc as I moved to SSD) and when I tried to extend the main partition size to include the new Unallocated Space it asked me if I wanted to convert the disc to Dynamic.  I simply pressed yes and the partition simply disappeared into unallocated space. All of my family pictures / videos lost.  After reading an article on Microsoft they said to recreate the partition with the same exact size, so I tried to do that but it didn't work. I did not format the drive at all when I created partitions.  How can I possibly recover the partitions?  Thanks! What solutions does the equation $4x\equiv2\mod10$ have? (Hint, it will have more that one.) What about solutions to an equation $ax\equiv d\mod n$, where $d=\gcd(a,n)$?  This is the question that appeared in our universities last year paper. But it seems very difficult for me like for first part I am able to solve by simplifications I got $x=5\cdot Z +3$ as solution which makes sense and seems fair but for the second one, I have no idea how can I approach that. Can you please help me out with that one. I tried to simplify that by using Euclidean algorithm but still, I didn't get any idea that what actually the solution will be. My final exam is on 2nd of next month and because of covid I am unable to contact in person for any help. So any help from this site will be appreciated. Thank you for looking at this question! Explanation behind Second Derivative of a Parametric Equation Formula I guess the proof of the identity $$ \sum_{n = 0}^{\infty} \frac{1}{n!} \equiv \lim_{x \to \infty} \left(1 + \frac{1}{x}\right)^x $$ explains the connection between such different calculations. How is it done? No error message if the URL is very long I entered a URL with a very long parameter on Stack Exchange.  I have type this url    It shows a blank screen , does not shown any messages.    We need to show a “Page Not Found” message, same as what you did on other Stack Exchange pages. This questions has been asked before too and I did go through most of the suggestions. Things I have tried so far: setting up correct  path variable environment, installing anaconda 32 bits, python 2.7, or even switching to python 2.7 in cmd while initially using Anaconda 3 , adding Desktop 10.4.pth file with  following path.  C:\Program Files (x86)\ArcGIS\Desktop10.4\bin C:\Program Files (x86)\ArcGIS\Desktop10.4\ArcPy C:\Program Files (x86)\ArcGIS\Desktop10.4\ArcToolBox\Scripts   I also added those paths in environment variable   These suggestions help me to reduce the error. But Now I am getting a different error. Looks like python can find arcpy but missing another package.  Getting this error while trying to import arcpy in python 3.6.   File "C:\Program Files (x86)\ArcGIS\Desktop10.4\ArcPy\arcpy\__init__.py", line 22, in &lt;module&gt;     from arcpy.geoprocessing import gp    File "C:\Program Files (x86)\ArcGIS\Desktop10.4\ArcPy\arcpy\geoprocessing\__init__.py", line 14, in &lt;module&gt;     from _base import *  ModuleNotFoundError: No module named '_base'   Any suggestions? What's the difference between JavaScript and Java? What's the difference between JavaScript and Java? possessive apostrophe for two things or persons What is the difference between the two sentences below? Are they the same or different in meaning?     Jack and Laura's new house is almost ready.      Jack's and Laura's new house is almost ready.   To my perception, the first says two of them have one house and the second says each one has a (different) house (which is almost ready). Is my perception correct?  EDIT: If I don't use "houses" instead of "house" (for my second interpretation), does it mean the sentence is wrong? Difference between projection and datum? Extra "lines" are being added when creating/editing questions/answers in Edge Lately, I've noticed that extra lines are being added when I create questions/answers. For example, if I write:   Your problem is X, Y, Z. Fix it by doing:      Code  Then maybe also do some other thing.  Oh, and some other thing as well.   When I post it, then go back into the editor, it's been changed to:   Your problem is X, Y, Z. Fix it by doing:       Code   Then maybe also do some other thing.   Oh, and some other thing as well.   Which is mildly annoying since that causes less to be displayed in the box at once, but whatever.  The weird thing is though, the added line isn't properly treated as a newline, even though it does appear to be caused by a newline. A lot of lines that look like they should be empty don't even get rendered. If I delete the original lines that I entered leaving only the "new" newlines, I get weird behavior:    I tried selecting the characters involved and inspecting them in Python, and they just appear to be newlines, so I have no idea what the problem is.    The only browser I've been able to reproduce it in is Edge (version 44.18362.329.0). It does not happen in Chrome. This has been happening for ~3 days now.    There is also a problem with link embedding and code formatting. If while editing I highlight some text and either try to embed a link (interlinked circle button) or format it as code ({} button), it often puts the wrong text between the […]s when embedding, or formats code that I didn't highlight (and doesn't format the code that I did highlight).