I just got a Lenovo ideapad 520, which includes a fingerprint scanner. It works fine for Windows, but when using Fingerprint GUI it simply doesn't detect the device. So I'm assuming I need a driver for this device, but I can't find any drivers online.  Does anyone know how to make this work in ubuntu 16.014?
I have a  with a fingerprint reader:    How to make Ubuntu recognise it and use it for login?  I already tried:  sudo add-apt-repository ppa:fingerprint/fingerprint-gui sudo apt-get update   ... but this GUI did not recognizes my device. Does anyone knows any other option?
Induction proof: n lines in a plane Assume that there are $n$ infinitely long straight lines lying on a plane in such a way that no two lines are parallel, and no three lines intersect at a single point. Prove that these lines divide the plane into $\frac{n^2+n+2}{2}$ regions. (Hint: Any two non-parallel straight lines on a plane must intersect at exactly one point.)  Can someone tell me where to start here? I know to prove the base where $n=0$, but don't know how to proceed.  Any help is greatly appreciated! What exactly is a hat?  I have seen a lot of people arguing the significance of hats and the limited edition hats. I know the hats are sort of linked to the Winterbash stuff, but what exactly is a hat, what does it do, how do I get one?  Is there a full list of hats? I recently read a lot about neural networks using GRU or LSTM units. There are many easy to use frameworks like tensorflow that do not even require high knowledge about programming. Unfortunately, I never really found good information on how the training of those networks work. Simple backpropagation might probably not work for gated recurrent networks or is just too inefficient for networks with such a high number of variables to learn.  So my question is:  What are the state-of-the-art algorithms used for the initialization and training of neural networks with GRU or LSTM units? I am not looking for frameworks to use, but for initialization and update equations for the internal parameters. Need a way to do a "loop cut" on a triangle fan Need a way to do a loopcut- ish thingy on the blue line I'm getting frequent inaccurate location as the same location, can I make this stop? When I open a window to air out the room, how does the smell disperse? Does new Star Wars continuity only affect post-Jedi EU? I have read  a couple of times.     In order to give maximum creative freedom to the filmmakers and also preserve an element of surprise and discovery for the audience, Star Wars Episodes VII-IX will not tell the same story told in the post-Return of the Jedi Expanded Universe.   Does this describe material set after Jedi, or published after?  Is it also saying that only things published as "Legends" are now non-continuity?  I have read that it is only films + Clone Wars + Rebels that are now in the main continuity but can't see this sourced by Lucas Film Story Group. Does anyone have a reference for this? Length of a JavaScript object I recently wiped my computer to have 14.10 as my only OS. It has 160 GB of storage. That was a month ago. Now, I keep getting prompts that the storage is almost full. And when I look it says I only have 543 MB free. How is this possible? I haven't torrented any large files. I do have Variety to autodownload wallpapers and not erase though.  Filesystem Size Used Avail Use% Mounted on  /dev/sda1  146G  138G  554M  100%  /  none 4.0K 0 4.0K 0% /sys/fs/cgroup  udev 742M 4.0K 742M 1% /dev  tmpfs 151M 1.1M 150M 1% /run  none 5.0M 4.0K 5.0M 1% /run/lock  none 752M 540K 751M 1% /run/shm  none 100M 80K 100M 1% /run/user –  er – Allowed Wave Functions of System Given a single-particle system with Hamiltonian $H$, what constraints can be put on the wave function at a particular point in time $\psi(x)$? Of course $\psi(x)$ must obey boundary conditions given by $H$. However, in situations where $H$ does not yield strict boundary conditions (e.g. the harmonic oscillator) can $\psi(x)$ be any normalised function? My intuition says no for the following reason: QM textbooks say that any valid wave function can be represented as a linear combination of the eigenstates of $H$. In the case of the harmonic oscillator, the eigenstates of $H$ are a countably infinite set. However the set of all normalised functions is uncountably infinite. It seems to me that one cannot change between one complete set of basis functions to another and reduce the "dimensionality" somehow. This makes me think that the eigenstates of $H$ are not complete, that they imply some constraints on $\psi(x)$. This is not an area of mathematics that I understand well. Can somebody help me out? Is the Ratio of Associative Binary Operations to All Binary Operations on a Set of $n$ Elements Generally Small? I started thinking about the number of associative (binary) operations on a set with $n$ elements today.  Looking online I found  which indicates only $113$ of the possible $19,683$ operations on a three-element set satisfy association.  So, $50\%$ of binary operations on a two-element set satisfy association, and less than $0.6\%$ of all binary operations on a three element set satisfy association.  For an $n$-element set, where $n$ denotes a natural number, is the ratio $R_{n}=A_{n}/B_{n}$, of the number of associative binary operations $A_{n}$ to the number of all binary operations $B_{n}$, in general small?  I don't mean the following questions as equivalent, but since they seem more concretely answerable in principle, does   $$ \lim_{n \to +\infty} \frac{A_{n}}{B_{n}} = 0 ? $$       Also, is $F : n \to R_{n}$ a monotonically decreasing function?  Some Background of the Question: In his Linear Algebra Problem Book 1995 on p. 6 Paul Halmos writes "The commonly accepted attitudes toward the commutative law and the associative law are different.  Many real life operations fail to commute; the mathematical community has learned to live with that fact and even to enjoy it.  Violations of the associative law, on the other hand, are usually considered by specialists only."  For all I know, Halmos might only have written that to motivate the study of Linear Algebra and doesn't quite literally mean what he appears to say.  But, if he means what he appears to say, and if $F : n \to R_{n}$ is monotonically decreasing, or $R_{n}$ is generally small, I think there's something amiss with what Halmos says, since non-associative operations seem so common that one may as well enjoy them. Check all dependencies of a Record Type in the Organisation before deactivating it I am looking forward to delete a Record Type in my Salesforce organisation. However before I go ahead and do the same I would love to know all of its dependencies in the entire org.  Please help me in finding a tool or a method to easily get all the list of dependencies associated with that particular record type.This may include ,  a)      Workflows/Process Flows b)      Validation Rules c)       Apex Triggers/Classes d)      Any other dependencies if we deactivate the record type.(including Picklist and Page layouts)  Thanks in advance. ASP.NET MVC Relative Paths In my applications, I often have to use relative paths. For example, when I reference JQuery, I usually do so like this:  &lt;script type="text/javascript" src="../Scripts/jquery-1.2.6.js"&gt;&lt;/script&gt;   Now that I'm making the transition to MVC, I need to account for the different paths a page might have, relative to the root. This was of course an issue with URL rewriting in the past, but I managed to work around it by using consistent paths.  I'm aware that the standard solution is to use absolute paths such as:  &lt;script type="text/javascript" src="/Scripts/jquery-1.2.6.js"&gt;&lt;/script&gt;   but this will not work for me as during the development cycle, I have to deploy to a test machine on which the app will run in a virtual directory. Root relative paths don't work when the root changes. Also, for maintenance reasons, I cannot simply change out all the paths for the duration of deploying the test - that would be a nightmare in itself.  So what's the best solution?  Edit:  Since this question is still receiving views and answers, I thought it might be prudent to update it to note that as of Razor V2, support for root-relative urls is baked in, so you can use   &lt;img src="~/Content/MyImage.jpg"&gt;   without any server-side syntax, and the view engine automatically replaces ~/ with whatever the current site root is. Problems with Curve Modifier Every time I think I have the curve modifier mastered, it throws me a another curve ball (no pun intended).  Why in  can I not get the lights to follow the spiral curve? When the modifier is activated, the lights are stretched and distorted along the curve.  I created the curve by converting it from a mesh (string of verts). Why does it not display like a normal Bezier? Is that related to my problem?  I am following all the "rules" that I am aware of, as detailed here: . The curve seems to run in the correct direction. The origin point is at the first point of the curve. The curve modifier on the lights is set to -Y which is the local orientation of the curve's direction.  What am I missing? I was working on a worksheet for class and came across this problem:      Let $\varphi:R\to S$ be an onto ring homomorphism with the property that every ideal of $R$ is principal. Show that the same must be true for $S$.    I honestly do not know how to do this one! Quickly create a large file on a Linux system How can I quickly create a large file on a Linux () system?   will do the job, but reading from /dev/zero and writing to the drive can take a long time when you need a file several hundreds of GBs in size for testing... If you need to do that repeatedly, the time really adds up.  I don't care about the contents of the file, I just want it to be created quickly. How can this be done?  Using a sparse file won't work for this. I need the file to be allocated disk space. Why does Java have an "unreachable statement" compiler error? I would like to format a price in JavaScript. I'd like a function which takes a float as an argument and returns a string formatted like this: &quot;$ 2,500.00&quot;  What's the best way to do this? Shape of a string/chain/cable/rope/wire? The height of a string in a gravitational field in 2-dimensions is bounded by $h(x_0)=h(x_l)=0$ (nails in the wall)  and also $\int_0^l ds= l$. ($h(0)=h(l)=0$, if you take $h$ as a function of arc length) .  What shape does it take?  My try so far: minimise potential energy of the whole string,  $$J(x,h, \dot{h})=\int_0^l gh(x) \rho \frac{ds}{l}=\frac{g \rho }{l}\int_0^l h(x) \sqrt{1+\dot{h}^2} dx$$  With the constraint  $$\int_0^l \sqrt{1+\dot{h}^2} dx- l=0$$ If it helps, it's evident that $\dot{h}(\frac{l}{2})=0$.  Generally, this kind of equation is a case of a constrained variational problem, meaning that the integrand in  $$\int_0^l \frac{g \rho }{l}h(x) \sqrt{1+\dot{h}^2} +\lambda(\int_0^l \sqrt{1+\dot{h}^2} dx- l)dx$$  Must satisfy the Euler Lagrange equation. The constraint must also be satisfied.  But, in truth, by this point I am clueless. $\lambda$ is worked through $\nabla J  = \lambda \nabla(\int_0^l \sqrt{1+\dot{h}^2} dx- l)$. I have tried this , but get nonsensical answers.  Is this method the best? If so, in what ways am I going about it wrongly thusfar? Explanation of the binomial theorem and the associated Big O notation