I would like to know how to enable the lightning app builder in my developer edition.  Thanks in advance. Best regards
I was googling unsuccessfully.   I've created Aura components without any problem, but I can't figure out how enabled this:     I'm trying to enable that feature in a Dev Winter 15.
Prove existence of disjoint open sets containing disjoint closed sets in a topology induced by a metric. How do I play a YouTube video in the background on my iPad? Fast way to come up with solutions to $x(x-1)(x-2)(x-3)=1$? I can solve this equation $x(x-1)(x-2)(x-3)=1$ using the usual method but I am looking for a fast analytical method to solve this. Any hints ? Can you flash any android device with "fastbood flash" command (of the adb)? C++ virtual function from constructor I needed to change the SID of an Oracle XE database (not the Service Name) to match a production database.  When I tried searching online, most of the pages were describing changing or adding a service name through tnsnames.ora; that's not what I needed to do. Constraints of relativistic point particle in Hamiltonian mechanics I try to understand constructing of Hamiltonian mechanics with constraints. I decided to start with the simple case: free relativistic particle. I've constructed hamiltonian with constraint:  $$S=-m\int d\tau \sqrt{\dot x_{\nu}\dot x^{\nu}}.$$  Here $\phi=p_{\mu}p^{\mu}-m^2=0$  $-$ .  Then $$H=H_{0}+\lambda \phi=\lambda \phi.$$   So, I want to show that I can obtain from this Hamiltonian the same equation of motion, as obtained from Lagrangian.  But the problem is that I'm not sure what to do with $\lambda=\lambda(q,p)$. I tried the following thing:  $$\dot x_{\mu}=\{x_{\mu},\lambda \phi\}=\{x_{\mu},\lambda p^2\}-m^2\{x_{\mu},\lambda\}=\lambda\{x_{\mu},p^2\}+p^2\{x_{\mu},\lambda\}-m^2\{x_{\mu},\lambda\}$$$$=2\lambda \eta_{\mu b} p^b+p^2\{x_{\mu},\lambda\}-m^2\{x_{\mu},\lambda\}=2\lambda \eta_{\mu b} p^b+p^2\frac{\partial \lambda}{\partial p^{\mu}}-m^2\frac{\partial \lambda}{\partial p^{\mu}},$$  $$\dot \lambda=\{\lambda, \lambda \phi \}=\{\lambda,\lambda p^2\}-m^2\{\lambda,\lambda\}=\lambda\{\lambda,p^2\}+p^2\{\lambda,p^2\}=2\lambda\eta_{ak}p^{a}\frac{\partial \lambda}{\partial x^{k}},$$  $$\dot p_{\mu}=\{p_{\mu},\lambda p^{2}-m^2\lambda \}=p^{2}\{p_{\mu},\lambda\}-m^2\{p_{\mu},\lambda\}=-p^{2}\frac{\partial \lambda}{\partial x^{\mu}}+m^2\frac{\partial \lambda}{\partial x^{\mu}}.$$  If we recall that $p^2-m^2=0$, then we get from the third equation: $\dot p=0$, and from the first: $$\dot x_{\mu}=2\lambda\eta_{ak}p^{a}.$$  So we have    $\dot x_{\mu}=2\lambda\eta_{\mu b}p^{b}.$ $\dot \lambda=2\lambda\eta_{ak}p^{a}\frac{\partial \lambda}{\partial x^{k}}.$ $\dot p=0.$   But I don't know what to do next. Can you help me? In the inline math mode ($...$), if the formula is too long, LaTeX will try to break it on operators, e.g.  very long text followed by a very long equation like $a+b+c+d+e+f+g+h+i+j+k+l$ etc   may be rendered as  very long text followed by a very long equation like a+b+c+d+e+f+g+h+i+ j+k+l etc   However, the break won't happen if they are separated by commas, e.g.  very long text followed by a very long equation like $a,b,c,d,e,f,g,h,i,j,k,l$ etc   will overflow the page like  very long text followed by a very long equation like a,b,c,d,e,f,g,h,i,j,k,l etc   How to make LaTeX able to insert line breaks after a comma too? How to run shell script via terminal What is a simple way to create a binary relation symbol on top of another? What is a simple way to have \ll on top of \gg with equal size and vertically center aligned and have them work as a binary relation symbol like \lessgtr? The commands \underset and \overset cannot be used because they do not treat the two symbols equally, and they do not vertically center. "Please do not repeat the mistake" and "Please do not repeat the mistake again" I have a VF page built on Lightning Design system (LDS) framework. When I add the renderAs="PDF" attribute, pdf does not show the content with LDS CSS/Style.  Reference Link:   Note1: apex:page tag has all the usual attributes which is required for pdf *     (showHeader="false" sidebar="false" standardStylesheets="false"   docType="html-5.0" applyHtmlTag="false" applyBodyTag="false")   Note2: Salesforce supports external stylesheet. That is, CSS file stored in Static resource. Link of example:   I also copied the whole css content from the LDS CSS file (Path: 'assets/styles/salesforce-lightning-design-system-vf.min.css') and applied as inline CSS in VF page. But still, there is no luck.  My styleSheet is referred in VF page as below  apex:stylesheet value="{!URLFOR($Resource.SLDS221,      'assets/styles/salesforce-lightning-design-system-vf.min.css')}"   Page works absolutely fine if it is not rendered as PDF.  Any suggestions? Generating hatched filling using Region functionality One server with multiple desktops "heads" with VNC I am managing a system of kiosks.  Each kiosk currently is running a web browser with the application for the kiosk running in the browser.  Each kiosk needs to be able to display separate content.  At times, the application running in the web browser freezes.  Thus, I have to go out to the site to refresh the page.  I want to see if there is a way to have one central server that has multiple browser heads.  Then each kiosk would run a program like VNC to display one of the heads.  This way when the program freezes, I just have to login to the central server and refresh the page.  Getting VNC or another remote desktop software installed on the clients is no problem.  What I am looking for is a way to have VNC remote into a specific head of a head of a web browser.  Does such a thing exist?  Or do I have to run a VM for each kiosk to remote into?  Any advice, pointers, or solutions would be helpful. Probability that the bag contains all balls white given that two balls are white A bag contains $4$ balls .Two balls are drawn at random and are found to be white.  What is the probability that all the four balls in the bag are white?.  The options are $\large\frac{1}{5}\space ;\frac{2}{5} ;\frac{3}{5} ;\frac{4}{5}$  My work: It's given that two balls are white.So the rest of the balls could be    all white One of them white none of them white   So among the three above possibilities only one satisfies our conditions so the probability is $\frac{1}{3}$.But it not even the options given. What's wrong with my work? Guarding against cryptanalytic breakthroughs: combining multiple hash functions Reason behind choosing the compensating resistor for input bias current in op amps I found the following explanation online on determining the values used for the compensating resistor:  In either case, the compensating resistor value is determined by calculating the parallel resistance value of R1 and R2. Why is the value equal to the parallel equivalent of R1 and R2? When using the Superposition Theorem to figure how much voltage drop will be produced by the inverting (-) input's bias current, we treat the bias current as though it were coming from a current source inside the op-amp and short-circuit all voltage sources (Vin and Vout). This gives two parallel paths for bias current (through R1 and through R2, both to ground). We want to duplicate the bias current's effect on the noninverting (+) input, so the resistor value we choose to insert in series with that input needs to be equal to R1 in parallel with R2.  Although it is a 'crisp' and simple explanation, I don't understand how it is true, since the current flowing through R2 won't directly go to the ground, but will probably enter the op-amp at the output (op-amp as a current sink). Also, it might go through a few more resistances before going to the ground, since Vout isn't directly connected to the ground. states that the isomorphism type of a finite simple group is determined by its order, except that:   $L_4(2)$ and $L_3(4)$ both have order $20160$ $O_{2n+1}(q)$ and $S_{2n}(q)$ have the same order for $q$ odd, $n &gt; 2$   I think this means that for each integer $g$, there are $0$, $1$ or $2$ simple groups of order $g$.  Do we need the full strength of the  to prove this, or is there a simpler way of proving it? Is there a picture showing all the lengths used in lists? "define:" oneboxing selects completely bogus data I found this weird word, "burke", and decided to check it out. It turned out it was an alternative spelling of "berk". This is what define: berk in chat expanded to:    So, according to that, "berk" as a noun can mean "a fool, prat, twit", or "berk", or "berk", or "berk". Wow, who would have thought "berk" might mean berk. Three times, just to be sure.  That got me really curious so I checked the wiktionary page directly. It shows three meanings for "berk": the same as meaning #1 that was oneboxed, plus two others that are not at all simply stated as "berk".  Further down from there we can find the other three "berks". Number three, for instance, is easy to trace since "indefinite plural berkë" seems quite greppable. And it turns out that it's Albanian.