How do I show the side bar (incl. available hard drives) when I open the file explorer Nautilus?
Nautilus does not show the left bar, how do I turn it back on?
General way to determine $\mathbb{Q}(\gamma) = \mathbb{Q}(\alpha,\beta)$ given $\alpha$ and $\beta$ Young adult book about a boy(?) who gets sent through a portal to another world which is really the distant future How to use the  method?  Say I want to find number of combinations I can get with $x_1+x_2+x_3+x_4=22$,  where $x_i\in\mathbb{N}$.  Is this the correct time to apply the method?  This is being repurposed in an effort to cut down on duplicates, see here:     and here: I'm a physics teacher and I would like to find a simulation software that could be used to give exact numerical answers to high school level problems in Newtonian mechanics.  I want the students to first calcultate a numerical answer to a physics problem and then use the simulator to visualize the problem in order to understand it better and verify that the simlator gives the same answer that they got when doing the calculation themselves.  Here are some examples of what kind of problems I want the students to be able to solve with the simulator:   A slope with a specific angle of inclination and a ball starts rolling at a certain point. Determine the speed, angular momentum and total mechanical energy of the ball after a specific time t. A ladder of known mass and length is leaning against the wall at a specific angle. The contact between the ladder and the wall is frictionless. Calcultate the x and y components of the force between the floor and the ladder.   I would like the software to have the following features:  - Simulation in 2D. No 3D simulations are necessary and the software should at least have the option of doing simulations only in 2D.  - Position all objects exactly by writing numbers (just positioning the objects using the mouse is not precise enough).  - Show animations of the time evolution of the system.  - Show forces, velocities and accelerations as arrows.  - Give exact numerical results so that the students can use the software to verify their calculation.  Ideally the software would have a graphical user interface, but if no suitable software with graphical interface exixts, I could also consider a software with text-based inputs. I would consider both free and commercial software.  My question is: Is there any software that would meet these requirements and if there is, where could I get it? Give each site a parallel site for polling, recommendations and subjective-ish stuff Suppose that $X$ is a topological space equipped with a delta-complex structure. Prove that $X$ is Hausdorff.  I can actually "see" why it should be Hausdorff after the hint from Hatcher asks to "think of a delta-complex X as a quotient space of a collection of disjoint simplices".  I would appreciate if somebody can write out a full formal argument showing this proof. I'm trying to start from the definition of Hausdorff but I don't know how to carry on. Custom script "invoked too many times" error Credit:   function getDirection(city1, city2, unit) {   var directions = Maps.newDirectionFinder()     .setOrigin(city1).setDestination(city2)     .setMode(Maps.DirectionFinder.Mode.DRIVING)     .getDirections();   var d = directions.routes[0].legs[0].distance.text;    var distance, value = d.split(" ")[0].replace(",", ""), text = d.split(" ")[1];   if(text == unit) {     distance = value;   } else if(text == "km" &amp;&amp; unit == "mi") {     distance = value / 1.6;   } else {     distance = value * 1.6;   }   return Math.round(distance); }   I have used this code snippet in one of my sheets. I am working on a dataset with roughly 6000 entries and I am getting some errors because of the large volume.      Script invoked too many times per second for this Google user account. (line 0).      Service invoked too many times for one day: route. (line 4).   I considered purchasing a Google Apps business account to increase my quota, but that might not even help. Do you maybe have any advice for me in this regard? How to prove  $$\int_{0}^{\infty} \mathrm{e}^{-x^2}\, dx = \frac{\sqrt \pi}{2}$$ urlEvent is undefined Can I include another file in fstab Can I include another file in my fstab file?  I.e. can I have fstab execute lines from another file at an arbitrary point, and then return to the main file when completed? Why is the CDF of a sample uniformly distributed I read  that given a sample $ X_1,X_2,...,X_n $ from a continuous distribution with cdf $ F_X $, the sample corresponding to $ U_i = F_X(X_i) $ follows a standard uniform distribution.  I have verified this using qualitative simulations in Python, and I was easily able to verify the relationship.  import matplotlib.pyplot as plt import scipy.stats  xs = scipy.stats.norm.rvs(5, 2, 10000)  fig, axes = plt.subplots(1, 2, figsize=(9, 3)) axes[0].hist(xs, bins=50) axes[0].set_title("Samples") axes[1].hist(     scipy.stats.norm.cdf(xs, 5, 2),     bins=50 ) axes[1].set_title("CDF(samples)")   Resulting in the following plot:    I am unable to grasp why this happens. I assume it has to do with the definition of the CDF and it's relationship to the PDF, but I am missing something...  I would appreciate it if someone could point me to some reading on the subject or help me get some intuition on the subject.  EDIT: The CDF looks like this: We know for a metallic conductor   Current $\frac{I}{enA} = v$ where $v$ is drift velocity , $e$ is the charge of an electron, $n$ is no of electrons per unit volume and $A$ is area of cross section.  Ok my questions that I am struggling with:   Does it depend on length of wire? (let's say if the current is the same and area is also the same but one wire is longer and one wire is shorter then is the drift velocity for both wires the same?) Does it depend on the cross sectional area of the wire? (Yes, according to the relation, if the area is greater, drift velocity is lower, correct?)   I have digged university physics still I couldn't get my answer :( . Why do we need to set swap space as twice big as our physical memory? When we want to setup a linux system, there is a common a suggestion to set the swap space  twice as big as your physical memory. I want to know why do we need this, and how it is this suggestion come to be? count vs length vs size in a collection From using a number of programming languages and libraries I have noticed various terms used for the total number of elements in a collection.  The most common seem to be length, count, and size.  eg.  array.length vector.size() collection.count   Is there any preferred term to be used? Does it depend on what type of collection it is? ie. mutable/immutable  Is there a preference for it being a property instead of a method? Some questions might be asked on three different sites, each site needing three different answers. For example, a question about a text editor.  So perhaps there should be a way to link the questions on the three different sites. Adding a link manually in the questions is certainly possible, but perhaps a feature officially supporting this will be beneficial. Writing test code for wrapper class How to work with Dried Mushrooms? I was recently given a bag of dried mushrooms and am unsure how to work with them.  What's the best way to use them? Forward/Inverse Search Does Not work on certain tex files Narrow-phase collision detection algorithms The  recommends that images have Copy-On-Write disabled on the directory when using btfs.  I do see that it would be a good idea if you had a lot of file read/writes.   question explores this idea.  I know that VMWare will grow into different files and will write snapshots out which could be problematic when using Copy-On-Write.  For QEMU the file is left open for the VMs existance so there is a potential problem in the write after the VM is shutdown, but I would see slow I/O after a VM is shutdown not being an issue.  What pitfalls would I be avoiding by performing this step for QEMU.    Additionally: I have assumed that the image is raw for this question.  Is there a possible stability issue as qcow2 already has copy-on write.