It seems to me, there are two broad categories of questions: (1) from people who use a programming language at their work place, and (2) from people who just started to learn using it. Almost everyone in the community seems to understand, based on the quality of the question, to answer the latter by initiating some thought and not just giving the solution.  I think, SO can do more to facilitate this. I am thinking about a special tag "beginner". Ideally, the actual accepted answer should not be revealed for questions tagged with such tags until clicked.  Do you think this would make sense? Maybe some other ideas?
See the revision history on , where the  tag was edited in (and subsequently edited out after I started this discussion).  I think, by adding this tag, you're making assumptions about the OP which they could find a little bit offensive.  Particularly with this question, there's no mention of the level of PHP knowledge — it's more a math question than it is a programming question. Someone could be excellent at a particular language whilst not being particularly great at math, so isn't it a bit insulting to make the assumption they're a beginner? It's also interesting to note  tag, which currently stands at 7,784 on SO.  Compare this to , which only has 18 questions, most of them being &quot;discussiony.&quot;  Why do users retag questions as &quot;beginner&quot; but not &quot;expert&quot;? UPDATE, , .  Related   (thanks @Ralph)
Why are properties lost in the Cayley–Dickson construction? The Find Familiar spell states, in part:  As an action, you can temporarily dismiss your familiar. It disappears into a pocket dimension where it awaits your summons.  The question arising from this is:  Is this pocket dimension different for every familiar in the world? Thus being a personal pocket dimension? If this is true, then it should be able to store items given by its master for safe keeping away from anyone else, as long as these are items that a familiar could carry with it. Can the familiar bring small items with it into the pocket dimension for safe keeping? I'm writing a script and I would like to pass the results from bc into a variable. I've declared 2 variables (var1 and var2) and have given them values.  In my script I want to pass the results from bc into another variable say var3 so that I can work with var3 for other calculations.  So far I have been able write the result to a file which is not what I'm looking for and also I've been able to echo the result in the terminal but I just want to pass the result to a variable at moment so that I can work with that variable.  echo "scale=2;$var1/var2" | bc Is there a name for this layout? Show that: $\lim\limits_{r\to\infty}\int\limits_{0}^{\pi/2}e^{-r\sin \theta}\text d\theta=0$ I would like to show $\lim\limits_{r\to\infty}\int_{0}^{\pi/2}e^{-r\sin \theta}\text d\theta=0$.  Now, of course, the integrand does not converge uniformly to $0$ on $\theta\in [0, \pi/2]$, since it has value $1$ at $\theta =0$ for all $r\in \mathbb{R}$.   If $F(r) = \int_{0}^{\pi/2}e^{-r\sin \theta}\text d\theta$, we can find the $j$th derivative $F^{(j)}(r) = (-1)^j\int_{0}^{\pi/2}\sin^{j}(\theta)e^{-r\sin\theta}\text d\theta$, but I don't see how this is helping.  The function is strictly decreasing on $[0,\pi/2]$, since $\partial_{\theta}(e^{-r\sin\theta})=-r\cos\theta e^{-r\sin \theta}$, which is strictly negative on $(0,\pi/2)$.  Any ideas? I just can't find a decent (and free) one. What can I use? If I have a dataset with a very rare positive class, and I down-sample the negative class, then perform a logistic regression, do I need to adjust the regression coefficients to reflect the fact that I changed the prevalence of the positive class?  For example, let's say I have a dataset with 4 variables: Y, A, B and C.  Y, A, and B are binary, C is continuous.  For 11,100 observations Y=0, and for 900 Y=1:  set.seed(42) n &lt;- 12000 r &lt;- 1/12 A &lt;- sample(0:1, n, replace=TRUE) B &lt;- sample(0:1, n, replace=TRUE) C &lt;- rnorm(n) Y &lt;- ifelse(10 * A + 0.5 * B + 5 * C + rnorm(n)/10 &gt; -5, 0, 1)   I fit a logistic regression to predict Y, given A, B and C.   dat1 &lt;- data.frame(Y, A, B, C) mod1 &lt;- glm(Y~., dat1, family=binomial)   However, to save time I could remove 10,200 non-Y observations, giving 900 Y=0, and 900 Y=1:  require('caret') dat2 &lt;- downSample(data.frame(A, B, C), factor(Y), list=FALSE) mod2 &lt;- glm(Class~., dat2, family=binomial)   The regression coefficients from the 2 models look very similar:  &gt; coef(summary(mod1))               Estimate Std. Error   z value     Pr(&gt;|z|) (Intercept) -127.67782  20.619858 -6.191983 5.941186e-10 A           -257.20668  41.650386 -6.175373 6.600728e-10 B            -13.20966   2.231606 -5.919353 3.232109e-09 C           -127.73597  20.630541 -6.191596 5.955818e-10 &gt; coef(summary(mod2))               Estimate  Std. Error     z value    Pr(&gt;|z|) (Intercept) -167.90178   59.126511 -2.83970391 0.004515542 A           -246.59975 4059.733845 -0.06074284 0.951564016 B            -16.93093    5.861286 -2.88860377 0.003869563 C           -170.18735   59.516021 -2.85952165 0.004242805   Which leads me to believe that the down-sampling did not affect the coefficients.  However, this is a single, contrived example, and I'd rather know for sure. Can HIV be transmitted via mosquitos? It is known that HIV is usually transmitted by direct blood or body fluid contact between an infected individual and a healthy person (like blood transfusion or needle sharing):  Suppose a mosquito bites an individual suffering from AIDS and in the process sucks up some T cells infected with HIV along with RBCs. Then it bites another person not suffering from the disease, and transfers these infected T cells. Isn't there a high probability of the second individual contracting HIV? I've created a new C++ project in Visual Studio 2008.  No code has been written yet;  Only project settings have been changed.  When I compile the project, I receive the following fatal error:     fatal error LNK1104: cannot open file 'C:\Program.obj' QGIS3 - Clipping polygons to a hemisphere for azimuthal orthographic projection I'm a bit of a novice with QGIS, so this is really throwing me for a loop.  For the maps I'm intending on making, an azimuthal orthographic projection would be my preference.   For example, one map I'm trying to recreate is this map of the Pacific islands :    I've been using the NaturalEarth Quick Start package, which has been a really good launching-off point, but I'm running into some issues at the horizon of the orthographic projection.  I've tried adding a custom projection:  +proj=ortho +lat_0=0 +lon_0=170 +x_0=0 +y_0=0 +a=6371000 +b=6371000 +units=m +no_defs   But that gives the following map:    Which certainly is close to being right, but the ocean is obviously being cut off in the Arctic and on the southern horizon.  I understand the issue is that naively mapping layers described in WGS 84 to an orthographic projection leaves you with artifacts at the horizon, but how do I fix it?    I first tried to use the Clip to Hemisphere plugin described in , but it seems incompatible with QGIS 3; when I try adding the plugin, QGIS3 gives an error message and places it in the "Invalid" section of the Plugins window.    I then tried both solutions presented at  Again the issue is with QGIS 2/3 incompatibility.    For Solution 1, both Numerical Digitize and CAD Tools are again incompatible with QGIS 3 and give the same result as Clip to Hemisphere.    For Solution 2, I can't disable on-the-fly-reprojection in settings since that setting was removed in QGIS 3. Let's say that there is a question asked in a bad manner, in a way that the question is missing. For example the user shows the code and doesn't explain very well which is the problem.    Usually someone starts digging in the OP mind posting comments and asking him for details. It may happen that the question gets edited and the OP edits it to a valid question.    Do you usually give the OP time to edit the question or you immediately vote to close it? In my cssh config file, I have:  terminal_font=6x13   this default font is too small for me.   man cssh says, I can specify other font size with the -f argument, while using "standard X font notation".  is a wikipedia page containing some other fonts types. Unfortunately, none of these work for me:  $ cssh host1 host2 -f "7x14" Fatal: Unrecognised font used (7x14). Please amend $HOME/.clusterssh/config with a valid font (see man page).   Why does "7x14" not work?  How can I use bigger fonts with cssh ? What is the need for Autobiographer badge? What is the reason that Autobiographer badge is kept in Stack Exchange?  This does not show any participation and people can just fill garbage to achieve this badge.   Is there a reason behind it? Retry a task multiple times based on user input in case of an exception in task I've seen plots of test/training error suddenly dropping at certain epoch(s) a few times during the neural network training, and I wonder what causes these performance jumps:    This image is taken from Kaiming He's Github, but similar plots show up in many papers. Record Animation In BGE At what point is a creature's toughness calculated? If I have  where I can sacrifice a creature and put X 1/1 token creatures onto the battlefield, where X is the sacrificed creature's toughness.  If I have a creature that is 4/4 and cast  to give it +3/+3 then sacrifice it? Do I get 4 tokens or 7?  Also what if my 4/4 creature was dealt 2 combat damage before I sacrificed it? Do I get 2 or 4 creatures?  Finally, what about counters? If my 4/4 had a +1/+1 do I get 4 or 5 tokens? requireJS optional dependency Clipping a figure to content Is it possible to clip a figure inserted with \includegraphics to contents? That is, remove all surrounding whitespace. prove that $\operatorname{lcm}(n,m) = nm/\gcd(n,m)$ I'm trying to prove that $\operatorname{lcm}(n,m) = nm/\gcd(n,m)$ I showed that both $n,m$ divides $nm/\gcd(n,m)$  but I can't prove that it is the smallest number.  Any help will be appreciated.