Anonymous methods vs. lambda expression
What's the difference between anonymous methods (C# 2.0) and lambda expressions (C# 3.0)?
Whats this white stuff on my board? I'm not an engineer, but my monitor stopped working yesterday (it just wouldn't display anything but still gets power) so I figured I'd like to take it apart and see what went wrong.  At the very least I'd get to see what the inside of a monitor looks like :).  Anyway, I took it apart, and also read around about my issue and it seems the capacitors have gone bad, at least some of them.  However, I also noticed some white elastic stuff all over the board.  Some of them are sticking two capacitors together and to the board, but I also see some from where power socket connects to the board.  My question is, what is the white stuff?  Should I replace all capacitors that have white stuff around it, and should I also replace the power socket part?  Or should I just replace the bulging capacitors and leave it at that?  UPDATE: Disable storage of invisible files "._" on my cfs or smb network storage One Object won't Show up in Final Render even though it shows up in the Preview Render I have a model of a building with a sidewalk around it.  Both show up when I switch to rendering mode in both Blender Render and Cycles Render mode.  But:  when I hit F12 for a final proper render, the building shows up -- but the sidewalk doesn't.    I've checked the normals and I thought the normals seemed pointed in the right direction.  I've set the Clipping on the Camera to a high number.  I removed all the materials from the sidewalk and added a new material-- the problem persists.  I've exported the blend as an FBX file and the Sidewalk shows up fine in Unity.  Just in final renders, it doesn't show up.    Here is a blend file: .  I tried to destroy everything unrelated to the issue and label things in a clear way.    Thanks. Books for a beginner I am a student of 11th grade and i have completed the syallabus of both 11th and 12th grade maths with complete understanding and it was possible coz of the love for this subject that i have. I don't want to sound "larger than life" here, but my curiousity has now increased to learn maths at a deeper level. As of now i am reading "Linear algebra done right" by Axler. Thats an amazing piece of work and now i truly understand what "matrix" is all about. I also want to extend my knowledge on the following topics :  1) Algebra (groups,subgroups,homomorphisms etc)   2) Analysis   3) Geometry/Topology  Why i am here is because i wanted you guys to recommend a book on each of the above topic that would be appropriate for a beginner like me (I must mention here I have been working on Apostol's volume 1 calculus, thats a great text, but for a beginner, its best if the concept is explained in a broad manner and in as simple and easy words as possible) . I just want a book which explains the concept broadly rather than coming to the conclusion directly (which is not a great sight for a beginner like me) .   Having said that, no book is complete i understand. Thats why i am asking your recommendation as you guys are aware which text would be the best to start with for a beginner. I have searched on the net about this, but there are dozens of works available, and out of them all , i want the one which is the best (approximation) for a beginner .   Please don't misunderstand me in any way. I am just confused which text to go for, and i understand the books which u may suggest may be for undergraduate level course as these topics are for undergraduate level courses, thats not a problem at all . I need a easy to learn (i mean easy in terms of "broad" explanation) book. I hope you guys don't mind me questioning such a question on this forum . Thanks for all the help you guys have been providing me on this forum . Maths Maths Maths... the world is beautiful coz of u! :)) This is, how I download various master branches from GitHub, and I aim to have a prettier script (and maybe more reliable?).  wget -P ~/ https://github.com/user/repository/archive/master.zip unzip ~/master.zip mv ~/*-master ~/dir-name   Can this be shorten to one line somehow, maybe with tar and pipe?  Please address issues of downloading directly to the home directory ~/ and having a certain name for the directory (mv really needed?). Connect Talend to Salesforce using OAuth JWT Flow I followed the steps exactly mentioned here  for connecting Talend to salesforce.  I have done the configuration in Talend and added the test(sandbox) URL in the advanced setting. I am facing an error while trying to establish the Oauth connection (JWT) between Talend ETL tool and salesforce: {'error':'invalid_grant','error_description':'invalid assertion'} Here is the screenshot of the configuration and error message:   Please help to resolve this issue. What process created the /var/lib/dpkg/lock-frontend file in Ubuntu? I have just booted my clean Ubuntu 18.04 LTS VM and tried to install some application with sudo apt install.  But got error message:     E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable)       E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?   What process created the /var/lib/dpkg/lock-frontend file in Ubuntu? How to gently stop it and take manual control on APT? Values of the limit $\lim\limits_{x\to+\infty}\left(\sqrt{(x+a)(x+b)}-x\right)$ Hi I have a question regarding finding the values of limit for the following question.  Let $a, b \in \mathbb R$. Find the limit $$\lim_{x\to+\infty}\left(\sqrt{(x+a)(x+b)}-x\right)$$ I'm sure there is a really simple explanation to this but haven't found any pointers on this forum or elsewhere. I seem to have lost the 'processing' menu from QGIS and can't figure out how/why!? Any ideas what I might have done to make this happen?  I'm running QGIS 2.8 built against GDAL 1.10 on Ubuntu 14.04. The Cartesian product of a finite number of countable sets is countable The Cartesian product of a family $(A_i\mid i\in I)$ is defined as $$\prod\limits_{i\in I}A_i=\{f:I\to\bigcup A_i\mid f(i)\in A_i\}$$ Let $I_n=\{i \in \mathbb N \mid i \le n\}$ for $n\in \Bbb N$ and $A_i$ be countable for all $i\in I_n$. Then $\prod\limits_{i\in I_n}A_i$ is countable.   My attempt: Lemma 1: $(\prod\limits_{i\in I_n}A_i) \times A_{n+1}$ and $\prod\limits_{i\in I_{n+1}}A_i$ are equinumerous for all $n \in \mathbb N$. (I presented a proof ) Lemma 2: If $A$ and $B$ are countable, then $A \times B$ is countable. (I presented a proof ) I will prove the theorem by induction on $n$. The theorem is trivially true for $n=0$. Assume that the theorem is true for $n=k$, then $\prod\limits_{i\in I_k}A_i$ is countable. Since $\prod\limits_{i\in I_k}A_i$ is countable (by inductive hypothesis) and $A_{k+1}$ is countable, then by Lemma 2 $(\prod\limits_{i\in I_n}A_i) \times A_{n+1}$ is countable. Furthermore, by Lemma 1 $(\prod\limits_{i\in I_k}A_i) \times A_{k+1}$ and $\prod\limits_{i\in I_{k+1}}A_i$ are equinumerous, then $\prod\limits_{i\in I_{k+1}}A_i$ is countable too. Thus the theorem is true for $n=k+1$. This completes the proof.   Does this proof look fine or contain gaps? Do you have suggestions? Many thanks for your dedicated help! If you multiclass a Warlock and a Sorcerer, then you have a character with both the Spellcasting and Pact Magic features.  PHB Page 101, Sorcerer, Spellcasting, Spell Slots:     You regain all expended spell slots when you finish a long rest.   PHB Page 107, Warlock, Pact Magic, Spell Slots:     You regain all expended spell slots when you finish a short or long rest.   PHB Page 165, Customization Options, Multiclassing, Class Features:     Pact Magic. If you have both the Spellcasting class feature and the Pact Magic class feature from the warlock class, you can use the spell slots you gain from the Pact Magic feature to cast spells you know or have prepared from classes with the Spellcasting class feature, and you can use the spell slots you gain from the Spellcasting class feature to cast warlock spells you know.   Do the spell slots keep their previous method of recovery (sorcerer slots long rest, warlock slots any rest), or do they all act consistently as I am led to believe from the language of the multiclass section? Do they all recover only from long rests as per the sorcerer feature, or can they all be recovered with a short rest because the warlock feature says so? Ubuntu 14.04 Wireless not working: no network interface. Atheros [168c:003e] device I just installed Ubuntu 14.04.3 LTS after installing windows 10 in my new VN7-571G and the wireless is not working. It never had: even during the installation it was not recognized. I run a script to gather the data , which is . lspci -knn | grep Net -A2 output 03:00.0 Network controller [0280]: Qualcomm Atheros Device [168c:003e] (rev 20)         Subsystem: Lite-On Communications Inc Device [11ad:0804]  The OS behaves like it has no wifi card. I do not see wifi settings in network settings I'm not a linux power user, so I do not know what to do to solve the issue. What should I do to make it work? In ZF, how would the structure of the cardinal numbers change by adopting this definition of cardinality? In ZFC, a good way of ordering sets by cardinality is by leveraging the notion of an injection. We define: $$X \lesssim Y \leftrightarrow \mbox{ there exists an injection } X \rightarrow Y.$$  Alternatively, we can leverage the notion of a partial surjection, by which I mean a partial function that hits every point of its codomain at least once.  $$Y \succsim X \leftrightarrow \mbox{ there exists a partial surjection } Y \rightarrow X.$$  Now in ZFC, these approaches are equivalent, in the sense that $$X \lesssim Y \iff Y \succsim X.$$  But if we just consider ZF (that is, we drop choice) then the equivalence breaks down. However, we've still got the forward implication, because the converse of an injection is always a partial surjection.  A specific question. Define that two sets are weakly equipotent iff $X \succsim Y$ and $Y \succsim X$. Question: does weak equipotence imply genuine equipotence? I'm guessing "no."  A general question: In broad terms, how would the structure of the cardinal numbers in ZF be altered by adopting $\succsim$ rather than $\lesssim$ as the fundamental order relation, and taking equality of cardinal numbers to correspond to weak equipotence of sets? I'm guessing this would hide a lot of the (usually very complicated) structure of the cardinal numbers in ZF.  Remark. The order symbols can be written \lesssim and \succsim. Split-like environment inside cases environment I'd like to have a cases environment with some cases that are too long to fit on one line. I tried this:  \begin{cases}   \begin{split}     long expression \\ second line of long expression   \end{split} &amp; condition \\   ...   but I get the warning     Package amsmath Warning: Cannot use 'split' here;   trying to recover with 'aligned' on input line 201.   It automatically replaces the split with an aligned environment, which looks like this:    Is there any way to get these long expressions to behave like they were in split or multline environments, with the top line flush left and the next line indented a little? Should Luke's lightsaber have given away his plan? During Luke's confrontation of Kylo Ren toward the end of The Last Jedi we see that       the lightsaber Luke uses a blue lightsaber (which I thought was his original one but that really doesn't matter), not the green one of his own construction.   Given that Kylo Ren  and Rey has just     fought over and broken the blue lightsaber   Why did Kylo Ren not notice this "inconsistency" and realize that      Luke's physical body was not there? Vertically align text next to an image? Why won't vertical-align: middle work?  And yet, vertical-align: top does work.   span{   vertical-align: middle; } &lt;div&gt;   &lt;img src="https://via.placeholder.com/30" alt="small img" /&gt;   &lt;span&gt;Doesn't work.&lt;/span&gt; &lt;/div&gt; I have just bought a Nikon 50mm f/1.8D prime lens.  I took this picture (leg of my glasses frame on a mouse, and a LED desk lamp is on top of it) : f1.8, 1/80s, ISO 200   The purple fringing is right in the middle of the picture. Does it happen very often to this lens? Automatically redirect anonymous user from unanswered duplicate question to corresponding answered version Duplicate questions that use different words to describe the same problem are important for people to find the content via search engines. But the user experience when an anonymous user arrives at a duplicate is less than ideal.  They have to notice the duplicate link and understand that the answer they are looking for is likely behind that link. I don't think this is all that obvious to someone without experience with an SE site.  I propose to just redirect users to the duplicate automatically if the closed duplicate has zero answers. In that case they need to follow the link to the duplicate in any case, so we might as well redirect them to it in the first place.  I could imagine this being problematic with search engines, as we would be displaying different content than what the search engines see. If that is too problematic I would suggest to show a very obvious link to the duplicate in the answers section for anonymous users. Are these plural or singular? I was surprised when I heard zero is plural, and even 1.00001 is plural.  Then, what about following numbers ?  (1) 1.00  which means the value measured  between 0.995-1.004, having possibility that it was exactly 1.  (2) 0.99999.....  which is mathematically equal to 1. Also, are others that are mathemattically equal to 1 than this, treated completely same as 1?  (3) -1  Is this singular? Or negative numbers are generally plural?  (4) i = square root of -1  I know it's weird to count things with imaginary numbers, nonetheless, if you were to count, which form, plural or singular, would you be to use?  That's it. Why is $R\cos{a} = mg$ in circular motion compared and not $R = mg\cos{a}$? Normally, if an object of mass $m$ is inclined to the horizontal at an angle $b$, we set the reaction force of the object on the inclined plane as $R = mg\cos{b}$ (if we resolve the force of gravity so the line of action coming out of the plane is perpendicular to it).  However in circular motion*. it's assumed that $R\cos{b} = mg$. In the example above, one would have to do this in order to arrive to the correct answer, instead of $R = mg\cos{b}$. Using $R = mg\cos{b}$ seems natural enough, as I am resolving vertically, however, both equations would produce two different values for $R$. Why is this?   To show what I mean: If we set the reaction force in this question as $mg\cos{a}$, then the centripetal force will be $mg\cos{b}\cos(\pi/2-b) = mg\cos{b}\sin{b} = \frac{1}{2}mg\sin(2b)$   Whereas If we use $R\cos{b} = mg$, $R = mg\sec{b}$ and the centripetal force will be $mg\sec{b}\sin{b} = mg\tan{b}$. This will end up with two different values for the radius of the circular motion, and hence two different final answers.  *In the circular motion questions I've seen in my mechanics module