If a resistor is suppose to resist over current to the load through a cable in a series DC circuit then why would you ever place a resistor on the positive cable side instead of the negative cable side. I mean that's where all the electric current with it's electric energy (negatively charged electrons) is coming out of to power the load with electric energy to DO WORK, and in this case too much of it before reaching the load and destroying the load. If the electrons with their electric energy charge were coming out of the positive side I would understand, but they don't...or do they.  -the question is in the title.  Edit: I don't want to know if or how the electrons KNOW what to do at the resistor. I want to know why would you put a resistor on the cable that's on the positive red side of the battery that doesn't supply any electrical energy/voltage/force to the load it just accepts electrons back into the battery.
With the following circuits as examples :    and    How will the current I know how much to flow? Would any other wave travel first in the circuit and then come back and say so much current should flow?
Suppose I have a python object x and a string s, how do I set the attribute s on x? So:  &gt;&gt;&gt; x = SomeObject() &gt;&gt;&gt; attr = 'myAttr' &gt;&gt;&gt; # magic goes here &gt;&gt;&gt; x.myAttr 'magic'   What's the magic? The goal of this, incidentally, is to cache calls to x.__getattr__(). How can I format to show text inside ""? I've posted a lot to StackOverflow, and I've noticed something kind of irritating with the formatting in writing questions and comments. If I need to put something inside a &lt; and a >, without spaces in the middle (like right there), it will think it's code and not show up, like this   (obviously it won't come up what I wrote there, or else this wouldn't be an issue, but if you open up the question to edit you can see what's written there.)  If I want it to show up, right now I have to add an extra set of brackets inside of the originals with a junk variable, like right &lt;here> (again, open in edit window to see).  This is really annoying when trying to show variables like lists that require those brackets, and I feel like the junk variables could confuse people looking at the edits. Is there a way to get around this formatting? Thanks! What WordPress API function lists active/inactive plugins? I want to copy any file to my external hard drive. But always when I tried to do this I have next output:  cp: cannot create regular file /media/NameOfCard/[file]' : Read only file system  I also tried:  sudo chmod -R 775 /media/NameOfCard sudo chmod -R 777 /media/NameOfCard   But the same effect - ... Read only file system  Update:   After mount I have next output:  nazar_art@nazar-desctop:~$ mount /dev/sda1 on / type ext4 (rw,errors=remount-ro) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) udev on /dev type devtmpfs (rw,mode=0755) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) /dev/sdb1 on /media/sdb1 type vfat (rw) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev) gvfs-fuse-daemon on /home/nazar_art/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=nazar_art)   Any suggestions?   How to solve this trouble and let permission to copy and delete files to hard drive? Customizing tray/taskbar date display in Ubuntu with GNOME 3 On previous versions I had the date displayed. Now it just shows the current day but not the day's number or the month.   Is there a way to customize the clock or tray/taskbar more in GNOME shell on Ubuntu 17.10 and later? Suggested reading for renormalization (not only in QFT) What papers/books/reviews can you suggest to learn what  "really" is?  Standard QFT textbooks are usually computation-heavy and provide little physical insight in this regard - after my QFT course, I was left with the impression that Renormalization is just a technical, somewhat arbitrary trick (justified by experience) to get rid of divergences. However, the appearance of Renormalization in other fields of physics  approach in statistical physics etc.), where its necessity and effectiveness have, more or less, clear physical meaning, suggests a general concept beyond the mere "shut up and calculate" ad-hoc gadget it is served as in usual QFT courses.   I'm especially interested in texts providing some unifying insight about renormalization in QFT, statistical physics or pure mathematics. How do I enumerate the properties of a JavaScript object? How do I enumerate the properties of a JavaScript object?  I actually want to list all the defined variables and their values, but I've learned that defining a variable actually creates a property of the window object. Is there any reason to use this-> I am programming in C++ for many years, still I have doubt about one thing. In many places in other people code I see something like:  void Classx::memberfunction() {     this-&gt;doSomething(); }   If I need to import/use that code, I simply remove the this-> part, and I have never seen anything broken or having some side-effects.  void Classx::memberfunction() {     doSomething(); }   So, do you know of any reason to use such construct?  EDIT: Please note that I'm talking about member functions here, not variables. I understand it can be used when you want to make a distinction between a member variable and function parameter.  EDIT: apparent duplicate: Audits bug in the filtered review queue Just recently the . I've got  this morning which seems to be out of scope for my filtered list. I have filtered my list to only review VBA and Excel-VBA tags while the audit is tagged with perl http pipes which have nothing in common with VBA. I see a problem with the way the system currently works  Since I have a filtered list of tags, once I see a differently tagged question I already know it's an audit. Come on, that's too easy!  Can this please be fixed? update I have ran into  which I decided to edit - the question was tagged VBA and I thought it had nothing to do with VBA so I selected Edit which was the correct action. Now, once the first audit was clearly one to close - nothing to do with VBA and really easy to know that it actually was an audit - the second one was a very good audit. I am just thinking now if this is a proper bug or just a matter of malfunction in the system. I think the first one may have been made an audit for the wrong reason. Let's turn this into a discussion as I can't clearly work the system out. On a series involving harmonic numbers Finding $$\sum^{\infty}_{n=1}\bigg[\bigg(\frac{(-1)^{n+1}}{n+1}\bigg)\bigg(\sum^{n}_{r=1}\frac{1}{r}\bigg)\bigg]$$   Try: Let $\displaystyle H_{n} =\sum^{n}_{r=1}\frac{1}{r},$ then series $\displaystyle \sum^{\infty}_{n=1}\frac{(-1)^{n+1}}{n+1}\cdot H_{n}=\frac{H_{1}}{2}-\frac{H_{2}}{3}+\frac{H_{3}}{4}\cdots\cdots$  could some help me to solve it, thanks Were these other people Chronicoms? We know that Enoch is a Chronicom, which is to say a sort of alien temporal observer.   When Enoch and his agents came and kidnapped       Coulson’s team,   for the purpose of sending them where they wanted; were these other agents also Chronicoms? I’m inclined to think they must have been (would Enoch have shared their advanced technology and goals, etc. with mere mortals), but on the other hand only one pod was mentioned. How can I deduce/identify an app from a notification icon? I'm concerned about an app on my child's phone. I saw an app icon in the notification area that looked strange (Andy Android head, slightly tilted as its icon).  How can I find out what app it is from just having seen that icon in the notification bar? How to request a random row in SQL? How to make a bootable ISO image from a bootable DVD? How can I fix a geoTiff with an incorrect CRS? Trying to load and plot a raster (it's a DEM) in R, but having problems.    Using R I read in a raster file:  library(raster)  dem &lt;- raster("DEM_Victoria.tif")  # &gt;70 MB print(dem)  class       : RasterLayer  band        : 1  (of  3  bands) dimensions  : 5444, 6007, 32702108  (nrow, ncol, ncell) resolution  : 100, 100  (x, y) extent      : 176615.6, 777315.6, 5650397, 6194797  (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +ellps=WGS84 +no_defs  data source : DEM_Victoria.tif names       : DEM_Victoria values      : 0, 255  (min, max)   My confusion here is the extent vs the CRS. The extent shows coordinates from a UTM Zone 55S system, while the CRS reports it as longlat.   Similarly, gdalinfo reports:  Driver: GTiff/GeoTIFF Files:  DEM_Victoria.tif Size is 6007, 5444 Coordinate System is: GEOGCS["GDA94",     DATUM["unknown",         SPHEROID["unretrievable - using WGS84",6378137,298.257223563]],     PRIMEM["Greenwich",0],     UNIT["degree",0.0174532925199433]] Origin = (176615.587999997427687,6194797.138000000268221) Pixel Size = (100.000000000000000,-100.000000000000000) Metadata:   AREA_OR_POINT=Area Image Structure Metadata:   COMPRESSION=LZW   INTERLEAVE=BAND Corner Coordinates: Upper Left  (  176615.588, 6194797.138) (Invalid angle,Invalid angle) Lower Left  (  176615.588, 5650397.138) (Invalid angle,Invalid angle) Upper Right (  777315.588, 6194797.138) (Invalid angle,Invalid angle) Lower Right (  777315.588, 5650397.138) (Invalid angle,Invalid angle) Center      (  476965.588, 5922597.138) (Invalid angle,Invalid angle) Band 1 Block=6007x1 Type=Byte, ColorInterp=Red Band 2 Block=6007x1 Type=Byte, ColorInterp=Green Band 3 Block=6007x1 Type=Byte, ColorInterp=Blue   Is this real? A problem? (well it is to me, but perhaps because I don't understand something) Fixable?  I tried 'Assign projection' in QGIS, which uses this command:  gdalwarp -t_srs EPSG:28355 -srcnodata -32768  DEM_Victoria.tif DEM_Victoria.tif.tmp   but it failed with:     ERROR 1: Too many points (12100 out of 12100) failed to transform,   unable to compute output bounds. MacBook [Pro] - how many displays, what resolution/frequency? Multigroup (CCK3) / FlexiField-like solution for compound fields? I've used  in the past to do multiply occurring series of field groups; now, working on a Drupal 7 project, I'm setting up a "Resume" content type and need a way to set up repetitive entries for education/work experience.   IE: for "Education", I need the ability to dynamically add new rows comprised of a combination of dates and places for each institution studied at.  What is the best way to accomplish CCK3 multigroup/FlexiField-like functionality in Drupal 7?  Thanks! In Spivak's Calculus 3rd Edition, there is an exercise to prove the following:  $$x^n - y^n = (x-y)(x^{n-1} + x^{n-2} y + ... + x y^{n-2} + y^{n-1})$$  I can't seem to get the answer. Either I've gone wrong somewhere, I'm overlooking something, or both. Here's my (non) proof:  $$\begin{align*} x^n - y^n &amp;= (x - y)(x^{n-1} + x^{n-2}y +\cdots+ xy^{n-2} + y^{n-1}) \\           &amp;= x \cdot x^{n-1} + x \cdot x^{n-2} \cdot y + \cdots + x \cdot x \cdot y^{n-2} + x \cdot y^{n-1}\\ &amp;\qquad + (-y) \cdot x^{n-1} + (-y) \cdot x^{n-2} \cdot y + \cdots + (-y) \cdot x \cdot y^{n-2} + (-y) \cdot y^{n-1}\\           &amp;= x^n + x^{n-1} y + \cdots + x^2 y^{n-2} + x y^{n-1} - x^{n-1}y - y^2 x^{n-2}  - \cdots- x y^{n-1} - y^n \\           &amp;= x^n + x^2 y^{n-2} - x^{n-2} y^2 - y^n  \\           &amp;\neq x^n - y^n \end{align*}$$  Is there something I can do with $x^n + x^2 y^{n-2} - x^{n-2} y^2 - y^n$ that I'm not seeing, or did I make a mistake early on?  EDIT:  I should have pointed out that this exercise is meant to be done using nine of the twelve basic properties of numbers that Spivak outlines in his book:     Associate law for addition   Existence of an additive identity   Existence of additive inverses   Commutative law for additions   Associative law for multiplication   Existence of a multiplicative identity   Existence of multiplicative inverses   Commutative law for multiplication   Distibutive law 2D Integration With Quadratic Arg. of Delta Function Impossible to hide navigation bars in Safari iOS 7 for iPhone/iPod touch