I have got Chromium browser 78  /usr/bin$ chromedriver -v ChromeDriver 78.0.3904.70 (edb9c9f3de0247fd912a77b7f6cae7447f6d3ad5-refs/branch-heads/3904@{#800})   This installs latest stable release  sudo apt-get install chromium-browser    I would like to downgrade to 77 but if I try this  sudo apt-get install google-chrome=77.0.3865.40 Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package google-chrome   How can I downgrade to Chromium 77 and switch off the upgrade?
How can I downgrade a package to an older version via apt-get?  Other tools are also acceptable but apt-get is preferred.
How to stop a sponge cake (chiffon cake) from deflating/sinking? Sum of infinite series $\sum_{i=1}^{\infty} \frac 1 {i(i+1)(i+2)...(i+n)}$ Lets define the following series $$S_n =\sum_{i=1}^{\infty} \frac 1 {i(i+1)(i+2)...(i+n)}.$$ I know that $S_0$ does not converge so let's suppose $n \in N$ and define $S_n$ for some $n$. We have $S_1=1$ , $S_2=\frac1 4$ , $S_3=\frac 1 {18}$ , $S_4=\frac 1{96}$ , $S_5=\frac 1{600}$ etc.. the numerator in all results is 1the pattern in denominator is $[1,4,1,96,600...]$ and   that is equal to $n*n!$ Finally I want to prove the general equality: $\sum_{i=1}^{\infty} \frac 1 {i(i+1)(i+2)...(i+n)}=\frac 1 {n*n!}$ Why is $\mathbb{R}^2$ not a subspace of $\mathbb{R}^3$? I cannot understand why $\mathbb{R}^2$ is not a subspace of $\mathbb{R}^3$.   My reasoning is as follows: Choose any elements $v_1$ and $v_2$ from $\mathbb{R}^2$, add them together you get an element of $\mathbb{R}^2$ and same for scalar multiplication and $0$ vector is an element of $\mathbb{R}^2$. So where did I go wrong? Trackpad not working after update to Ubuntu 14.10 on Dell Inspiron 15R When I updated from 14.04 to 14.10 I noticed my track-pad cursor and left and right mouse clickers were not working. I have tried looking this issue up and can not find any solutions anywhere. If anyone could help me that would be amazing, I am using a wired mouse to my USB port for a temporary fix. I have a Dell Inspiron 15R. Duo of alien xenologists study couple of Terran explorers, later save them How do I get add-apt-repository to work through a proxy? Which countries require a 24-hour transit visa in China? I'm transiting through China in Kunming, China.  I'm a South African national and do NOT fall under the 72-hour visa free program. However on [their official (travelchina) website][1] it says:     Nationals of most countries are eligible for the 24-hour direct   transit, while a visa is needed for the passengers transiting on   Afghanistan, Azerbaijan, Iran, Iraq, Kazakhstan, Kyrgyzstan, Malaysia,   Nigeria, Oman, Pakistan, Saudi Arabia, Sri Lanka, Thailand, Turkey,   United Arab Emirates and Yemen passports.   I'm sorry if I'm missing this, but the above is rather badly worded for me does "nationals of most countries" include ALL countries except those mentioned in the list shown?  Also again sorry if I'm missing this but again it is rather badly worded for me. I will fly via Thailand to China and then via China to Canada with an 8-hour layover in China. I see Thailand is mentioned on the list. I have a Thailand residency permit where I currently reside... Would that affect me at all?  Also, any idea if I can exit the airport in China and come back under the 24-hour visa exemption (should I be exempt)?  Many thanks. Where in the registry does Windows store with which program to open certain file types? After installing Adobe PDF reader, it opens files with the .PDF file extension. Ones' default web browser opens .html files and notepad opens .txt files, etc.  Where exactly in the registry are these filetype - program associations stored in the registry?   In other words, how does Windows know with which software/program it must open a certain file(type)? How to recover a deleted file from /data partition? How accurate is approximating the Earth as a sphere? What level of error do I encounter when approximating the earth as a sphere? Specifically, when dealing with the location of points and, for example, the great circle distances between them.  Are there any studies on the average and worst case error compared to an ellipsoid? I'm wondering how much accuracy I'd be sacrificing if I go with a sphere for the sake of easier calculations.  My particular scenario involves directly mapping WGS84 coordinates as if they were coordinates on a perfect sphere (with the  defined by the IUGG) without any transformation. What's the best way of checking if an object property in JavaScript is undefined? jQuery: live() vs delegate() I have a qualifying exam coming up in a couple days and I am just trying to understand some pathological examples I have in my notes. I will list a similar problem which I know the solution to and then the question.  True or False:   let $A,B \in \mathbb{Q}^{n \times n }$  Suppose $xI-A$ and $xI-B$ are equivalent then $\det(xI-A) = \det(xI-B)$.     I wrote in my notes this is true because any two matrices are equivalent in $\mathbb{Q[x]}^{n \times n}$ if and only if they have the same invariant factors.  Since the characteristic polynomial is a product of the invariant factors it follows that $\det(xI-A) = \det(xI-B)$.        True or False:   let $A,B \in \mathbb{Q}^{n \times n }$. If $\det(xI-A) = \det(xI-B)$ (in $\mathbb{Q}[x]$) then $xI-A$ and $xI-B$ are equivalent  in $\mathbb{Q}[x]^{n \times n}$   I think this is false because of the fact that equality of determinants is not strong enough to guarantee all invariant factors are equal but I do not have an example. What is the best way to check whether a given object is of a given type? How about checking whether the object inherits from a given type?  Let's say I have an object o. How do I check whether it's a str? How to print fields value in views-view.html.twig in drupal 8 How to print fields value in views-view.html.twig I have created a views-view.html.twig file for my view slider_3. The template name is 'views-view--slider_3.html.twig' The view formatting is done by this template, but I need a field is come at begging position of the view:  &lt;div class="slider-3-main"&gt;{{ rows.required_field }} &lt;div{{ attributes.addClass(classes) }}&gt;   {{ title_prefix }}   {% if title %}     {{ title }}   {% endif %}   {{ title_suffix }}    How can be the field will written to display at {{ rows.required_field }} Cannot see Samba configuration tool in the Dash in ubuntu 14.04 After a fresh installation of ubuntu 14.04 (my previous installation has seen to be broken somewhere reading .wmv file with VLC), I've installed Samba GUI tool from the software center.  It briefly appears in the launchpad then disappears. From this time I cannot the see in in the dash.  I've found this in askUbuntu   but the command sudo apt-get install samba samba-common gives me nothing to install.  Lecture des listes de paquets... Fait Construction de l'arbre des dépendances        Lecture des informations d'état... Fait samba est déjà la plus récente version disponible. samba passé en « installé manuellement ». samba-common est déjà la plus récente version disponible. Les paquets suivants ont été installés automatiquement et ne sont plus nécessaires :   kde-l10n-engb kde-l10n-fr Veuillez utiliser « apt-get autoremove » pour les supprimer. 0 mis à jour, 0 nouvellement installés, 0 à enlever et 8 non mis à jour.   The following guide  has no result either.  Any idea ?  Laurent06000 I am flying from Orange County, California to San Francisco, California and then on to Seoul, South Korea. If I check a bag will I have to pick it up in San Francisco and re-check it and go through security or customs for the international flight?  Everything I am reading leads me to believe that it's only necessary to re-check baggage and go through security and/or customs when you are first arriving into a country. However, since my first leg is staying within the United States I assume the airline will transfer my bag to the next flight and I can just go straight to the gate for my international flight?  Both legs of the flight are through the same airline (United Airlines) and there are only the two legs: OC -> SF, then SF -> Seoul. Blocking comment spam without using captcha Delimiter is being changed with fields I have a file with values organized in columns, and separated by commas, as in the file below:   324,01,1,113333600000,1,, 016,01,1,134954200000,1,, 770,01,1,109069200000,1,, 853,01,1,111518800000,1,,   When I use the following awk command, the delimiter is being changed from commas to spaces   Code:  awk -F, '{$4=$4/1024}{print $0}'   The output becomes:   324 01 1 110677343.75 1   016 01 1 131791210.93 1   770 01 1 106512890.62 1   853 01 1 108905078.12 1    How can I change the value of the field without changing the delimiter? How to see an embedded image's dpi (ppi) in a pdf in Acrobat Pro? The following situation baffled me slightly: after preparing a pdf in a different program I wanted to make sure that an embeded image in the pdf file had the right dpi, yet I found no way in adobe acrobat pro to inspect the file/image dpi.   Can that be, or am I missing where this feature is hidden?