One answer to multiple questions?
Is it acceptable to add a duplicate answer to several questions?
Are global variables bad? What should I consider when choosing continuous lighting vs. strobes for studio photography? Why do my LED lights stay on, even when the switch is off? I have two LED lamps in my corridor, and when I switch them off, they keep emitting light (not very strong, but it's annoying at night).  What can it be? How can I fix it? So here is the problem      Solve $$4^x + 6^x = 9^x$$ for $x$.   I am trying to find its real solution.  I was trying in this way!! $$6^x\left( \frac {4^x}{6^x} + 1\right) = 9^x$$ $$\left({\frac 23}\right)^x +1=\left({\frac 32}\right)^x$$ but I'm stuck . . . Will anyone help ? What type of solder is safest for home (hobbyist) use? Jackknife vs. LOOCV How do I watch a file for changes? I have a log file being written by another process which I want to watch for changes. Each time a change occurs I'd like to read the new data in to do some processing on it.  What's the best way to do this? I was hoping there'd be some sort of hook from the PyWin32 library. I've found the win32file.FindNextChangeNotification function but have no idea how to ask it to watch a specific file.  If anyone's done anything like this I'd be really grateful to hear how...  [Edit] I should have mentioned that I was after a solution that doesn't require polling.  [Edit] Curses! It seems this doesn't work over a mapped network drive. I'm guessing windows doesn't 'hear' any updates to the file the way it does on a local disk. At college we use ArcGIS Desktop 10, but that does not function on my Mac so I have QGIS there instead.  I want to do my exercises with QGIS, but in ArcGIS Desktop we use .lyr files with ArcMap and .lyrx files with ArcGIS Pro, and they are not supported by QGIS.  Does anyone know, how I can connect the *.lyr files to my *.shp files to use them on my Mac with QGIS? This is purely a curiosity, but I'm fascinated by mid-word pluralization, even if the word in question is a compound word.  For example, passersby or standersby.  No others have occurred to me. Can you provide other examples, or a link to a resource that enumerates them?  I'm particularly interested in compounds that do not include spaces or hyphens. When I have Excel running and I double click an Excel file in Windows explorer, I'd like it to launch in a new window by default so that I can move documents to separate monitors. Is there any way to get this behavior? Poking around the people's profiles to see how the  I keep seeing things like this:  It looks strange to have a 25/5 progress on a badge, but the dialog explains that what this user is missing is a positive record of asking. The  is: (total questions - negative questions - closed - deleted)/total questions &gt;= 0.5  If you look at , it's hard to see how his asking record could be anything but exceptional. According to  his asking record is 0.875. The problem is that he asked many of his questions in the early days of the site that were well-received, but later deleted. Some were deleted after the question was . My suggestion is that we change the asking record formula: (total questions - negative questions - closed - early deleted)/total questions &gt;= 0.5  The early deleted variable counts only questions deleted within 60 days of being asked. I picked 60 days because it's the dividing line between being able to . After looking through the list of people who would get the Curious badge on Stack Overflow with this change, I noticed a few things:  Many of them have self-deleted questions on their record. Often these are questions that were asked and basically ignored. After a few months, the original asker went back and deleted their question. It's hard to know what happened in each individual case, but my guess is that they never found a solution to their specific question and worked around the issue instead. (I have a few of those, but I'm not courteous enough to delete them.)  These users don't tend to ask the same question over and over again. I ran a similar test that excluded self-deleted questions. That group included a lot of cases of people asking a question, not getting an answer after a day or two, deleting the question, and asking the same question again. This strategy doesn't work if you wait two months to delete your first question.  Two mods (George Stocker and Gordon), Tim Post, and myself are on the list of users who would get a Curious badge under this system. On Meta Stack Exchange 5 current employees would be newly eligible for the badge. In my (admittedly biased) opinion, these are curious users.  I did some spot check on the lower end of the reputation scale. Every user I looked at fit my model of the ideal recipient of the Curious badge; they asked mostly upvoted questions with few closed questions. This change would add about 3286 new Curious badges on Stack Overflow, so there will certainly be a few exceptions I didn't find. But I think they are more than balanced by the clearly deserving users who will be awarded new badges.    Proposal: For the Curious, Inquisitive, and Socratic badges, don't count questions deleted 60 or more days after asking as deleted for the purposes of calculating asking record. These questions may still count as negatively scored or closed, if applicable. Days that include deleted questions, no matter when they are deleted, do not count toward the days asked criteria.   Modified Proposal: For the Curious, Inquisitive, and Socratic badges, don't count questions deleted or closed 60 or more days after asking as deleted or closed for the purposes of calculating asking record. These questions may still count as negatively scored, if applicable. Days that include deleted or closed questions, no matter when they are deleted or closed, do not count toward the days asked criteria. On Stack Overflow, that would add about 665 Curious badges, including two more for moderators (casperOne and 0x7fffffff) and one for an employee (Oded). On the opposite end of the reputation scale my spot checks are a bit muddier. Instead of a small number of deleted (and usually closed) questions, this list turns up users whose latest questions still aren't all that interesting. Even so, on balance a few extraneous bronze badges seem worthwhile in exchange for acknowledging truly curious users. Exit from both root and user with one command I know about "not using sudo su -" etc. But let's be honest, almost all of us do it.   So, here is the issue. We can't have root logins enabled, so we have to ssh in as our user then su to root.  Here is the process tree:       1  7897  7826  7826 ?           -1 S     1000   0:00 sshd: josh@pts/0  7897  7898  7898  7898 pts/0     8182 Ss    1000   0:00  \_ -bash  7898  7990  7990  7898 pts/0     8182 S        0   0:00      \_ sudo su -  7990  7991  7990  7898 pts/0     8182 S        0   0:00          \_ su -  7991  7992  7992  7898 pts/0     8182 S        0   0:00              \_  -su  7992  8182  8182  7898 pts/0     8182 R+       0   0:00                  \_ ps axjf   I would like to exit from root, then from my user with one command. Is there a way to do this?  BTW exit &amp;&amp; exit does not work because it exits the shell and doesnt process the rest of the command  josh@ubuntu:~$ sudo su - root@ubuntu:~# exit &amp;&amp; exit logout josh@ubuntu:~$ Using Laptop Screen as a monitor How can I use JavaScript on the client side to detect if the page was encrypted? Is it possible to detect, on the client side, whether the user is using an encrypted page or not?  Put another way -- I want to know if the URL of the current page starts with http or https. Every time I call \section{**Section Name**}, a number appears to the left of the name of the section.  How do I hide this number? Need to understand parallel query execution error Today we experienced a degradation in performance on our production sql server.  Durring the time this occurred we logged several "The query processor could not start the necessary thread resources for parallel query execution" errors.  The reading that I've done suggests that this has to do with how many CPUs to use when executing a complex query.  However when I checked during the outage our CPU Utilization was only at 7%.  Is there something else this could be referring too that I haven't come across yet?  Is this a likely culprit of the performance degradation or am I chasing a red herring?  My sp_configure values for this are as follows:  name                                minimum maximum config_value run_value cost threshold for parallelism      0       32767   5            5 Heisenberg famously derived his uncertainty principle by considering the disturbance that a measurement would have on a small enough system.  Of course in the mathematical formalism of Quantum Mechanics the relationship is derived from more basic principles.  How does String Theory account for it? Heuristically, and mathematically? Pointing the camera in a particular direction programmatically I'm trying to use Python to place a camera. I know the camera's location, and the forward and up vectors for the camera (i.e. the direction it's pointing and its orientation). How do I do this?  I know that it's possible to calculate a raw world matrix from the above information, which I can then apply to the camera, but I was rather hoping not to have to. Is there an easier way? Group files in some folders I have some files with different extensions such as *.pdf, *.mp3, *.jpg and a few others. All of them are stored in a parent directory.  How can I get a list of all extensions, create some folders based on these  extensions and then move all files into their relevant folders? Training N classifiers for N labels vs one classifier with N labels I have a classification problem which is multi-label with N labels. I would like to know which method would be the better choice? Training N classifiers (1 for each label) or a single classifier which use K-hot encoding. I'm using a neural network for this with a softmax at the last layer. (Is there any chance that the softmax would cause a problem?) I'm using tensorflow for the model.