Unable to assign value to variable using "document.getElementById.value"
What is the scope of variables in JavaScript?
Let $\mathbb{F}$ be a finite field.  Let $a_1,\dots,a_n \in \mathbb{F}$ be given.  I want to know whether there exists $x_1,\dots,x_n \in \mathbb{F}$ such that  $$a_1 x_1^2 + a_2 x_2^2 + \dots + a_n x_n^2 = 1.$$  My question: Can we characterize when this equation has a solution, i.e., by some criterion on $a_1,\dots,a_n$?  Is there a clean characterization, in terms of $a_1,\dots,a_n$ and the properties of $\mathbb{F}$?    Here's what I can see immediately.  First, if $n=1$, there is an easy answer (the equation has a solution iff $a_1$ is a square in $\mathbb{F}$).  Second, if any $a_i$ is a square in $\mathbb{F}$, the equation has a solution (set all other $x_j$'s to $0$), so we can assume that all the $a_i$'s are non-squares and that $n \ge 2$.  Third, if $-1$ is a square in $\mathbb{F}$, then the equation has a solution: we can take $x_2 =  \sqrt{-a_1/a_2} \cdot x_1$.  But what about the case where $-1$ is a non-square in $\mathbb{F}$?  Is it always guaranteed to have a solution in this case? I am trying to rename my Windows / Boot Camp partition from "EFI Boot" to "Boot Camp" or "Windows". But I do not figure out where to rename.   I tried bless command on the NTFS Volume, I tried creating the folders "System/Library/CoreServices" and copied the .disklabel file into it (or also blessit) but nothing changed.  Finally I got the Volume Icon on Boot Selection to work by copying the icns File onto the EFI partition. Also tried blesson the EFI partition – but this also do not work.  So I have my Icon, but I also would like to rename it – how can I do this?  Systems are Windows 10 and macOS Mojave. sample make file for creating more than one exe files with different directory Can you use Magical Secrets to choose high level spells when multiclassing as a Bard? Say you have a Wizard 7/Bard 9. You gain your 17th level and choose to gain the level in Bard (which grants you Magical Secrets). According to the Multiclass Spellcaster: Spell Slots per Spell Level table, you now have a single 9th level spell slot. Can the spells you choose from Magical Secrets be 9th level spells even though you can only cast up to 5th level Bard spells? Showing that $\displaystyle\lim_{s \to{1+}}{(s-1)\zeta(s)}=1$ I need prove the following: ($\zeta(s)$ is the Riemann zeta function)  $\displaystyle\lim_{s \to{1+}}{(s-1)\zeta(s)}=1$  I really don't know, I have tried hard, but have obtained nothing for now. Concatenate multiple files with two blank lines as delimiter? I'm trying to join Markdown files with two newlines between each file.   I've tried using the following command:  paste -sd '\n\n' file1.md file2.md   This joins the files with a newline, but not two newlines, as I need.   What command can I use to join an arbitrary number of files with two \n characters between each join? $(\Bbb R,+)$ is a topological group. Is there any other group structure on $\Bbb R$ such that it is still a topological group and this group is not isomorphic to $(\Bbb R,+)$ ?  Refer to  for the general problem. In that problem I have conjectured that there is no such group however I couldn't prove it. Can't access my home directory "Encrypted private directory is not setup properly" Hi I'm trying to access my home directory on my laptop hard drive through a live usb. I cannot boot into the OS on the hard drive and the home and root directory is encrypted. I have the encryption key but when I try to run the tool to gain access it pops up for a second then disappears and when I run the command in Terminal it says "Encrypted private directory is not setup properly". What are my options on getting into the directory? I really need to get the data off my laptop. What counts as "entering a zone"? There are many actions that create persistent zones and have a trigger for their effect of among others: "...enters the zone..." What are the things that qualify as entering the zone?  Things that would seem to fit this would be:   Willing movement into the zone. Forced movement into the zone. Teleporting into the zone. Appearing inside the zone. Having the zone moved to include the square you occupy.   Do any of those listed not count as having entered the zone and why? And are there any that are not listed that would count as having entered the zone?  This is for D&amp;D 4e. What would be an appropriate opposite of "exceed"? launchd plist format for running a command at a specific time on a weekday What can I do when getting “This question body does not meet our quality standards”? While trying to ask a question, I got the error message     This question body does not meet our quality standards. Please make sure that it completely describes your problem - including what you have already tried - and is written using proper grammar.    Why am I getting this message? What can I do to get the system to accept my question? Can you be more specific? What are good resources on how to ask high-quality questions?      For more information, see  in the . How does one use circular polarizers? Looking for a short story about a robot evolving to have supernatural powers I'm looking for a short story from about 50 years ago about a robot who escapes after being slated to be melted down and discovers while in hiding that it has evolved to have some supernatural powers. When we're dealing with problems in electrostatics (especially when we use Gauss' law) we often refer to the density of electric , which is inversely proportional to the radius in the case of a single point charge (all field lines are directed radially).   My question may sound dumb, despite the fact that this concept is quite intuitive, but if you think about it there is actually an infinite amount of field lines which we can draw everywhere (one through every point), so speaking of an area where field lines are more "dense" or "sparse" doesn't make much sense to me.  With this in mind, why can we still use such a concept? Why does it really work? Invest money and get 120% back - a site says I was talking to a friend who owns a Mac. He has his set up so that when he swipes three fingers across his touchpad, it moves to the workspace in that direction. Is it possible to set this up in Ubuntu? Cannot Buy Land in Falkreath Turning water pump on/off using Arduino Uno R3 I'm trying to build a simple system to turn a water pump every 24 hours for 10-20 seconds. I have 5V pump. When I connect it to 5V, GND it works but when I connect it to pin 12 (or any other digital pin) and GND it does not work. Here's my sample sketch:  int led = 12;  void setup() {                   Serial.begin(9600);   pinMode(led, OUTPUT);      }  void loop() {   digitalWrite(led, HIGH); }   What am I doing wrong? Parsing date/time string with timezone abbreviated name in Python?