I am doing this Java question :     Jalaj purchased a table for Rs.200.4 and due to some scratches on its   top he had to sell it for Rs.176.5. Find his loss and loss%.      LOSS : Cost Price - Selling Price      LOSS% : (LOSS/Cost Price)*100      a. Declare four double variables i.e. costprice, sellingPrice, loss,   lossPercentage      b. Assign 200.4 to costPrice and 176.5 to sellingPrice.      c. Print loss and lossPercentage according to the given formulas like:   823.67 8.23 d.      For printing upto two decimal places use  System.out.printf("%.2f\n", loss);       Note:         output for both should be upto two decimal places   Output should be displayed in two different lines      My code:  /*Write your code here */ import java.util.Scanner; class bkws{     public static void main(String args[]){         double costPrice,sellingPrice,loss,lossPercentage;         costPrice=200.4;         sellingPrice=176.5;         loss=costPrice-sellingPrice;         lossPercentage=(loss/costPrice)*100;         System.out.print("%.2f",loss);         System.out.println("%.2f",lossPercentage);     } }   Now I am thinking of using Math.round but for rounding off to 2 decimal places it should be:  Math.round(number*100)/100;   But it is giving error and I also want to know that if there is any easy way to round off to n decimal places without using Math.round in Java.
What I would like is a method to convert a double to a string which rounds using the half-up method - i.e. if the decimal to be rounded is 5, it always rounds up to the next number. This is the standard method of rounding most people expect in most situations.  I also would like only significant digits to be displayed - i.e. there should not be any trailing zeroes.  I know one method of doing this is to use the String.format method:  String.format("%.5g%n", 0.912385);   returns:  0.91239   which is great, however it always displays numbers with 5 decimal places even if they are not significant:   String.format("%.5g%n", 0.912300);   returns:  0.91230   Another method is to use the DecimalFormatter:  DecimalFormat df = new DecimalFormat("#.#####"); df.format(0.912385);   returns:  0.91238   However as you can see this uses half-even rounding. That is it will round down if the previous digit is even. What I'd like is this:  0.912385 -&gt; 0.91239 0.912300 -&gt; 0.9123   What is the best way to achieve this in Java?
Algebraic proof of $\sum_{i=0}^k{{n \choose i}{m \choose {k-i}}}= {{m+n}\choose k}$ I can't figure out an algebraic proof for the following identity:  $$\sum_{i=0}^k{{n \choose i}{m \choose {k-i}}}= {{m+n}\choose k}$$  Combinatorical solution:  We can see that as choosing some from $n$ and the rest of $k$ from $m$, thus $k$ in total.  Or we could just choose $k$ from the union. How do I send all information in /var/adm/message file to a remote system? I'm trying to figure out how to send all information that is normally identified in the /var/adm/message file on a Solaris system to a remote system. I get the following error when trying to ls *.txt | wc -l a directory that contains many files:  -bash: /bin/ls: Argument list too long   Does the threshold of this "Argument list" dependent on distro or computer's spec?  Usually, I'd pipe the result of such big result to some other commands (wc -l for example), so I'm not concerned with limits of the terminal. Why the Principle of Least Action? On-screen keyboard popping up whenever I touch screen I'm in 17.10. Whenever I touch the screen, whether to change windows/apps, scroll within a browser, or press a button, the stupid little keyboard pops up in the bottom left corner.  I have never left Screen Keyboard enabled in Universal Access, but if I toggle it on, that's the same keyboard popping up in the bottom left corner.    In this screenshot, I'm simply touching the screen in a full-screen youtube video. You can see the menu pop up on the right, under the point where I'm touching.  I don't have a before pic, but it was similar look/color keyboard, but it was smaller, maybe half as wide, and only in the bottom left section of the screen, as opposed to stretching across the entire width. This change from little left-hand keyboard to full-width keyboard happened after following @pomsky 's advice below.    This is a . You can mark yourself affected by it to hopefully increase its received attention. Is Poly1305 an information-theoretically secure MAC? How can I figure out what's slowly eating my HD space? Plotting an epicycloid unicode-math broken Prove that $$1+\frac{1}{3}+\frac{1\cdot 3}{3\cdot 6}+\frac{1\cdot 3\cdot 5}{3\cdot 6 \cdot 9}+.........=\sqrt{3}$$   $\bf{My\; Try::}$ Using Binomial expansion of  $$(1-x)^{-n} = 1+nx+\frac{n(n+1)}{2}x^2+\frac{n(n+1)(n+2)}{6}x^3+.......$$  So we get $$nx=\frac{1}{3}$$ and $$\frac{nx(nx+x)}{2}=\frac{1}{3}\cdot \frac{3}{6}$$  We get $$\frac{1}{3}\left(\frac{1}{3}+x\right)=\frac{1}{3}\Rightarrow x=\frac{2}{3}$$  So we get $$n=\frac{1}{2}$$  So our series sum is $$(1-x)^{-n} = \left(1-\frac{2}{3}\right)^{-\frac{1}{2}} = \sqrt{3}$$  Although I know that this is the simplest proof, can we solve it any other way someting like defining $a_{n}$ and then use Telescopic sum.  Thanks. How do I calculate the probability density function for a joint beta + uniform distribution? The PDF of a Beta distribution is $$ f_X(x) = {{x^{a-1}(1-x)^{b-1}}\over {B(a,b)}}  $$ and CDF $$ F_X(x) =  I_x(a,b) $$ The PDF of a uniform distribution is $$ f_Y(y) =  {1 \over {b-a}} \space for \space  x \in [a,b] $$ and CDF $$ { x - a} \over {b - a} $$ I've know that if X and Y are two independent, continuous random variables, described by probability density functions above of $f_X(x)$ and $f_Y(x)$ then probability density function of $Z = XY$ is $$  f_Z(z) = \int_\infty^\infty f_X(x)f_Y({z\over x}){1\over abs(x)}dx  $$ but I'm struggling with the algebra to get  from this to the PDF and the CDF of the joint distribution. I'm using the uniform distribution between 0 and 1. Problem with sudo apt update in Ubuntu 18.04: Post-Invoke-Success if /usr/bin/test -w /var/lib/command-not-found/ The terminal gave me these errors when updating the software with sudo apt update.    Hit:1 http://it.archive.ubuntu.com/ubuntu bionic InRelease Hit:2 http://it.archive.ubuntu.com/ubuntu bionic-updates InRelease                                                                                        Hit:3 http://it.archive.ubuntu.com/ubuntu bionic-backports InRelease                                                                                      Hit:4 http://security.ubuntu.com/ubuntu bionic-security InRelease                                      Hit:5 http://archive.canonical.com/ubuntu bionic InRelease                 Traceback (most recent call last):                       File "/usr/lib/cnf-update-db", line 8, in &lt;module&gt;     from CommandNotFound.db.creator import DbCreator ModuleNotFoundError: No module named 'CommandNotFound' Reading packages list... Done E: Problem executing scripts APT::Update::Post-Invoke-Success     'if /usr/bin/test -w /var/lib/command-not-found/ -a -e /usr/lib/cnf-update-db;       then /usr/lib/cnf-update-db &gt; /dev/null; fi'   E: Sub-process returned an error code     These are the results of sudo apt install --reinstall command-not-found  Reading package lists... Done  Building dependency tree         Reading state information... Done 0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded. Need to get 0 B/5.188 B of archives After this operation, 0 B of additional disk space will be used. (Reading the database ... 225797 files and directories currently installed.) Preparations for extracting ... / command-not-found_18.04.4_all.deb ... Extracting command-not-found (18.04.4) on (18.04.4) ... Configuring command-not-found (18.04.4) ... libdvd-pkg: Package libdvdcss2-1.4.2-1 was removed, stop processing...   When I tried the command sudo apt update again after reinstalling command-not-found, the results were the same as described in the first text block. Why is Ubuntu Software Center dropping previously provided applications? Ubuntu Software used to provide Pinta, KolourPaint, Audacity, and others, but they are no longer available there. I have to use apt to install them.   Why has Ubuntu Software 3.20.5 stopped providing applications that it used to?  Ubuntu 16.04 Ubuntu Software Center 3.20.5  Thanks in advance for your help! How do I show that there exists variational/action principle for a given classical system? We see variational principles coming into play in different places such as Classical Mechanics (Hamilton's principle which gives rise to the Euler-Lagrange equations), Optics (in the form of Fermat's principle) and even General Relativity (we get Einstein's equation from the Einstein-Hilbert action). However, how do we explain this very principle, i.e., more mathematically, I want to ask the following:      If I am given a set of generalized positions and velocities, say, $\{q_{i}, \dot{q}_{i}\}$, which describes a classical system with known dynamics (equations of motion), then, how do I rigorously show that there always exists an action functional $A$, where    $$A ~=~ \int L(q_{i}, \dot{q}_{i})dt,$$    such that $\delta A = 0$ gives the correct equations of motion and trajectory of the system?    I presume historically, the motivation came from Optics: i.e., light rays travel along a path where $S = \int_{A}^{B} n ds$ is minimized (or at least stationary). (Here, $ds$ is the differential element along the path). I don't mind some symplectic geometry talk if that is needed at all. How do I use '&' literally in LaTeX? How do I remotely wake my Mac over Wi-Fi? To flag or not to flag question that don't show own effort? I am a little confused about what do with questions that are just asking      "I want this and that (...) and I want it to look exactly like that   (...) please help"   without showning ANY own effort?  According to  those kind of answers are not welcome  also the  says those questions should not be asked:     Don't ask about...   Questions you haven't tried to find an answer for (show your work!)   But does this mean that I should flag those kind of "helpdesk" questions or not? And if yes as what? low quality ? flag for moderator attention ? Or is just adding a kind comment asking for the asker's own attempts enough? How do I select elements of an array given condition? Is it possible to extend a tourist Schengen visa (12 more days)? Missing links to responses to comments on nomination posts In the responses tab in my profile, responses to comments on nomination posts include a working link in the page source, but because there's no title the links are empty and useless.    When listed in the inbox such posts do have a title, though in this case the link is to the post and not directly to the comment. (Actually, the links in responses end up being redirected and also go to the post and not to the comment, but they try to go to the comment.)  In Supercollider:    In Global Profile: