i upgraded from 18.04 MATE to Ubuntu 20.04 MATE. After upgrading the graphics are unstable. I tried a live version of 20.04 from a USB stick and got the same result.  Ended up reinstalling 18.04 and the graphics are fine. I don't know if it's a GPU driver issue or something else.  Computer: Dell Precision 380 tower (desktop) GPU: Nvidia NV42GL Quadro FX 3450/4000 Graphics driver: Nouveau
I just ordered the Nvidia GTX card. I have a dilemma, though. Should I keep using the driver which is available in "additional drivers" in Ubuntu, or should I install the driver from the Nvidia site?  So which driver is the best for me?
How to install software provided in software-center via terminal? MacOS 10.14 Mojave public beta public Wi-Fi problem I can not connect to a single public Wi-Fi hotspot that does not require a password but instead shows a pop-up window pointed to captive.apple.com  The pop-up opens blank with the error "The web page couldn't be loaded"  Any idea on how to fix this? Installed Teamviewer using a 64-bit system, but I get a dependency error When does the set enter set theory? Is every open subset of $ \mathbb{R} $ uncountable? Is every open subset of $\mathbb{R}$ uncountable?  I was crafting a proof for the theorem that states every open subset of $\mathbb{R}$ can be written as the union of a countable number of disjoint intervals when this question came up.  I feel like the answer is yes, but I'm not sure how to go about proving it or whether there is a crazy construction (like the Cantor Set)  that creates a countable, open subset of $\mathbb{R}$. Any ideas? I see lots of tutorials telling me how to root my phone (Motorola Droid), but none of them mention any potential "side effects."  Aside from a few relatively minor issues that seem to require rooting to fix, I'm basically happy with the phone and therefore a little leery of messing with a device that cost me a lot of money and is only a few months old.  Assuming that I'm just talking about rooting, and none of the typical post-root actions (like installing a custom ROM), am I taking any risks by choosing to root?   Does it have the potential to brick the device? Will it void my warranty? Will I stop getting updates? Will the cops show up at my front door the next day? (Yes, I'm being facetious.) Anything else I should be aware of?   (See also: ) How do you get a timestamp in JavaScript? Something similar to Unix's timestamp, that is a single number that represents the current time and date. Either as a number or a string. Here's the scenario...    if (entry.Properties["something"].Value != null)   attribs.something = entry.Properties["something"].Value.ToString();   While effective and working correctly, this looks ugly to me.  If I don't check for a null before performing the ToString() then it throws an exception if the property was null.  Is there a better way to handle this scenario?  Much appreciated! Pass a PHP string to a JavaScript variable (and escape newlines) What is the easiest way to encode a PHP string for output to a JavaScript variable?  I have a PHP string which includes quotes and newlines.  I need the contents of this string to be put into a JavaScript variable.  Normally, I would just construct my JavaScript in a PHP file, à la:  &lt;script&gt;   var myvar = "&lt;?php echo $myVarValue;?&gt;"; &lt;/script&gt;   However, this doesn't work when $myVarValue contains quotes or newlines. $f\geq 0$, continuous and $\int_a^b f=0$ implies $f=0$ everywhere on $[a,b]$ If the plural of ‘man’ is ‘men,’ shouldn’t the plural of ‘German’ be ‘Germen’? What makes these two words so different that 'man' is changed to 'men', but 'German' is changed to 'Germans'? How can I get more of this macro photo in focus? Is "data" treated as singular or plural in formal contexts? My non-native English speaking friend just asked me: "Data is..." or "Data are..."?  I said both but that's because I've been desensitized from reading/writing both (especially from writing code and adding quick comments).  My question: Is it acceptable to utilize either for a university paper? Or is one safer than the other (when confronted with stickler professors)?    Related questions: Show that $\langle x,y\rangle_A = \langle Ax,Ay\rangle$ is an inner product on $\mathbb R^n$ Let $A$ be an $n \times n$ matrix with real enteries. Define $\langle x,y\rangle_A = \langle Ax,Ay\rangle, \quad x,y \in \mathbb R^n$ , where $\langle,\rangle$ is a standard inner product on $\mathbb R^n$. Then  $\langle x,y\rangle_A$ is an inner product iff  1)  $\ker A = \{0\}$.  2) $\operatorname{rank} A= n$.  3) all eigenvalues of $A$ are positive.  4) all eigen value of $A$ are non negative.  Clearly if $\ker A \neq \{0\}$, then there exist $x \neq 0$ such that $Ax =0$, then $\langle Ax, Ax\rangle_A = 0$, then $\langle ,\rangle_A$ is not inner product, so $\ker A = \{0\}$, thus rank of $A$ is $n$.  I am unable to check the 3) and 4) option. Please help to check the other option. Thank you I want to install Win Xp on my Ideapad Z 570 laptop but i always get blue screen with message with some drive related problem which asks me to run CHKDSK command. I tried with that but no luck. Is there any way i can install Win Xp with SP 2 ?  Edit: i searched across the sites and came to know there could be some Compatibility problems, and i could fix it by setting HDD mode to IDE; will it solve the problem? Ubuntu 20.04 graphics driver problem I have upgraded from Ubuntu 19.10 to 20.04, and now I have a problem with my graphics rendering (strange squares on background and font problems). I use the i915 driver. Graphics card: Skylake GT2 HD Graphics 520. I tried to reinstall GNOME shell and Xorg server. Nothing helped. Also Chrome browser breaks on most of pages. Egyptian fractions with prime power denominators summing to 1? Inspired by        Can we solve the equation $$1=\frac{1}{a_1}+\frac{1}{a_2}+\frac{1}{a_3}+\cdots +\frac{1}{a_n}$$ where $a_1,a_2,a_3,\cdots ,a_n$ are distinct prime powers (primes are allowed) ?   I tried a modified greedy-algorithm with different starting vectors and brute force with $6$ entris with limit $200$, but did not find a representation. Canonical copies of sets Sometimes one needs two disjoint copies of a given set $X$. This can be canonically done by taking $\{0\} × X$ and $\{1\} × X$. Sometimes we want to identify one of the copies with the original set $X$. So I wonder, is it possible to take a disjoint copy of $X$ straight ahead? And can this be done canonically? More precisely, are the following claims true? $ \def\dom{\operatorname{dom}} \def\rng{\operatorname{rng}} \def\On{\mathbf{On}} $   For every $X$ there is a one-to-one function $f$ such that $\dom(f) = X$ and $\rng(X) ∩ X = ∅$. There is an explicit formula $φ(X, f)$ such that for every $X$ there is exactly one $f$ satisfying $φ(X, f)$ and this $f$ satisfies 1. for $X$.   Since such construction of a disjoint copy is intuitively trivial, I'm interested in proofs of 1. and 2. without using regularity, choice, or infinity.   Some ideas:   We may simply put $f(x) := (x, X)$, but we need regularity to show that $(x, X) ∉ X$. We may consider $α = \sup(X ∩ \On)$ and pair members of $X$ with some ordinals above $α$, but we need AC to well-order $X$, and we need global choice to obtain 2. Let $&lt;$ be the transitive hull of $∈$. If the relation $&lt;$ is narrow, i.e. $\{y: y &lt; x\}$ is a set for every $x$, then we may choose $z ∉ ⋃\{(\leftarrow, x)_&lt;: x ∈ X\}$ and put $f(x) := (x, z)$ since $(x, z) = y ∈ X$ would imply $z &lt; y$. Note that we don't need the axiom of infinity to define $&lt;$, but I don't know how to prove its narrowness without infinity. "He committed a crime killing/by killing a bird" Which wording with kill should be used here:     He committed a crime (killing/by killing) a bird.   My guess is the answer would be by killing. But I am really confused with the answer killing.   My questions relating to this sentence are:   Which one is correct and why? (or are they both correct?) If one of them is incorrect, why is it incorrect? (or, if both of them are, why?) If they are both correct, what is the difference in meaning? If they are both correct, what is the difference in their grammar? pgfmathanglebetweenpoints always returns 90