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Why is integration the inverse of differentiation Why is integration the inverse of differentiation, I mean why do I get the same function when I integrate and then differentiate the result? I have a new computer with a Seagate ST500DM002 SATA internal hard drive.  I am trying to install Ubuntu 11.10 64-bit on it but the installer does not recognize/detect/see the hard drive. When I reach the Installation type step, the panel which is supposed to show devices and partitions looks empty.  sudo fdisk -l shows only /dev/sda1, the USB drive from which I am running the installation. I have already tried the following two solutions without any success:   sudo apt-get remove dmraid Switch the SATA mode in the BIOS from IDE to AHCI   I am sure it's not a hardware related problem as I have already successfully installed another operating system on the same computer.  The output of sudo lshw -class storage -class disk follows:    *-ide UNCLAIMED                 description: IDE interface        product: ASMedia Technology Inc.        vendor: ASMedia Technology Inc.        physical id: 0        bus info: pci@0000:06:00.0        version: 01        width: 32 bits        clock: 33MHz        capabilities: ide msi pm pciexpress cap_list        configuration: latency=0        resources: ioport:d040(size=8) ioport:d030(size=4) ioport:d020(size=8) ioport:d010(size=4) ioport:d000(size=16) memory:fe400000-fe4001ff   *-storage        description: SATA controller        product: 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller        vendor: Intel Corporation        physical id: 1f.2        bus info: pci@0000:00:1f.2        logical name: scsi1        version: 05        width: 32 bits        clock: 66MHz        capabilities: storage msi pm ahci_1.0 bus_master cap_list emulated        configuration: driver=ahci latency=0        resources: irq:44 ioport:f0b0(size=8) ioport:f0a0(size=4) ioport:f090(size=8) ioport:f080(size=4) ioport:f060(size=32) memory:fe705000-fe7057ff      *-cdrom           description: DVD-RAM writer           product: DVDRAM GH22NS70           vendor: HL-DT-ST           physical id: 0.0.0           bus info: scsi@1:0.0.0           logical name: /dev/cdrom           logical name: /dev/cdrw           logical name: /dev/dvd           logical name: /dev/dvdrw           logical name: /dev/scd0           logical name: /dev/sr0           version: EX00           capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram           configuration: ansiversion=5 status=nodisc   *-scsi:0        physical id: 1        bus info: usb@1:1.2        logical name: scsi6        capabilities: emulated scsi-host        configuration: driver=usb-storage      *-disk           description: SCSI Disk           physical id: 0.0.0           bus info: scsi@6:0.0.0           logical name: /dev/sda           size: 14GiB (16GB)           capabilities: partitioned partitioned:dos           configuration: signature=0004e5a4   *-scsi:1        physical id: 2        bus info: usb@1:1.3        logical name: scsi7        capabilities: emulated scsi-host        configuration: driver=usb-storage      *-disk           description: SCSI Disk           product: Storage Device           vendor: USB Mass           physical id: 0.0.0           bus info: scsi@7:0.0.0           logical name: /dev/sdb           capabilities: removable         *-medium              physical id: 0              logical name: /dev/sdb   Any idea on what I could do to fix this problem? I make use of the view: "taxonomy term". Is there an easy way to also show the children of a term, next to the nodes beloging to this term?  Example:  Cars - Volvo --- Family_cars --- Sports_cars - Honda --- Parts --- ... Trucks - ...   When you see the "cars" page I want to show all articles about cars (but not about Volvo, Honda, ...) AND I want to show the children (Volvo, Honda, ...) When you click one of these I want to show all the articles belonging with them, again with their children. Is there a good casual online place to practice/learn bridge? I know that Pogo.com (which powers Yahoo Games) has a long running online bridge game and that there are a handful of places for serious tournament/MasterPoint level bridge players online (though most seem based on software written a decade or more ago) but are there any places to play, practice and learn bridge in a more casual manner? Ideally via a well designed modern piece of software? The boundary of union is the union of boundaries when the sets have disjoint closures Most descriptions of SIGTERM and SIGKILL point out that SIGKILL,     In contrast to SIGTERM and SIGINT, [...] cannot be caught or ignored [...] ()   Is this the only difference between SIGTERM and SIGKILL? In particular, if a process does not install a SIGTERM handler, is there any difference at all between sending SIGTERM or SIGKILL to the process? What's the difference between scaling text via transform and changing font size? Is there a difference between using Transform commands to scale text and altering the size of the font via Character panels?   I'm working in Photoshop CC Why does comparing strings using either '==' or 'is' sometimes produce a different result? Add a message when posting to old questions with more than N answers My system is not dual-boot, I run a standard Ubuntu desktop system "on the metal" (I think running it in a VM is the same).  Pressing c while booting does not cause the GRUB menu to appear (which I believe it does for a dual-boot system).  How can I get the GRUB-menu to present itself on a single-boot system? Z-axis issue with the floating review info panel, permits various elements to flow over it I was having a look at an old question of mine when I browsed the  from the timeline. I scrolled downwards and realized the Review completed panel comes along for the ride. While that might be , tags flowing over top of it as pictured below probably isn't.  Here's a .gif of the Question and Duplicate tabs flowing over it as well. Note that the timeline button also flows over. If vote buttons are present, they will also flow over it.  Reproduced on Chrome and Microsoft Edge. Update Per  by Tiago Martins Peres, this issue also happens in other Review types, namely Late Answers, First Posts and Low Quality Posts. In addition to that, it is causing the action buttons on reviews to become unclickable if you scroll low enough.  As a temporary workaround, you can use 's , which  this issue. This is a canonical question that will hopefully encompass all of the questions we get asking us to determine what year a bicycle was manufactured (how old is my bike, how old is my frame, etc.). Each "answer" should address a different way to determine the manufacturing year of a bicycle. To some extent, these will also help you narrow down the model as well as it will tell you what distinguishing features to look at.  The span of answers would include things such as:      Skiptooth cranks Cartridge bottom brackets (BB30/90 etc) Elliptical chainring Quick releases versus contemporary through-axles How the steerer attaches to the fork (quill vs. threadless)  Braking system (especially with mountain bikes: v-brake, direct pull, etc.)   Shifting ramps and pins on cassettes/sprockets and chainrings (versus flat sprockets) Frame material (e.g., shift from tubular steel to use of CF and hydroformed aluminium)  Frame tubing type (e.g. Reynolds 531 tubing introduced around 1934, still used today; Reynolds 501 tubing introduced around 1983). So a frame with an original 501 decal can't be from the 70', 531 decal doesn't help as much because of the range of years produced. Also, see Decals.   *Decals: style/design, amount, placement, color, etc. can help not only determine models, but also year of manufacture. Many changed decal design for the same model bike often yearly, with special/limited editions even more specific. This applies only if decals are original or have been replaced with the identical design. Tubing decals (Reynolds, Columbus, etc.) also changed designs for same tubing made in different years, although the changes aren't made as often, and manufacturers didn't always put tubing Brand decals on every model. Earlier bikes tended to have less fancy, less colorful, less quantity of decals.   Headbadges: most early bikes had actual "badges", often quite detailed and fancy, made of metal, then plastic, and finally just using decals on the headtube. Most bikes lost their metal badges in the 60's and early 70's, although some brands still have actual badges to this day, but in general a real badge indicates an earlier model bike. Dropout style (including the later inclusion of lawyers lips) Presence or absence of CPSC reflectors (USA only) Manufacturing method (shift from lugs to TIG welding, for example)  Number of gears (shift from 2x5 ten-speed to 3x8, 2x9, 1x11, etc.)  Inspection of lug design: pantographs, cut-out, stampings, custom brazing/filing, chrome, fork crow n sweep, etc. Frame/Fork Braze-ons. Race bikes tended have less braze-ons the earlier the year of manufacture. Most 60's racers and earlier had few or none with cable guides/stops, shifters, bidons, etc. being clamp-on. By the 80's if it was clamp-on, it was a sign of very cheap models and most frames had braze-ons for all cables, with multiple bottle and accessory bosses depending on style and use.   and so forth. Please edit this question if you have an answer that isn't in the index above.   A couple of caveats:   A previous owner could have replaced or upgraded components on a bicycle, so this guide only applies to original equipment There is a delay between the introduction of a technology (such as indexed shifting) and when manufacturers start selling products that use it. Low-end manufacturers may continue using technology that is severely outdated (such as one-piece cranks, freewheels, or quill stems) because it is cheaper to do so. A number of bikes are built in a Retro style, but with modern components.  Dutch bikes, trendy coffee cruisers, and beach cruisers may be modern but appear to be 1950s styling.  These tend to have modern rims and brakes as a giveaway.     Note that bicycles.stackexchange does not do valuations of bicycles. How much your bicycle is worth depends on the location of the buyer and seller, how much the buyer wants the bike, etc. etc. etc. Change Default Scrolling Behavior of UITableView Section Header Hi I would like to know whether the trace of the inverse of a symmetric positive definite matrix $\mathrm{trace}(S^{-1})$ is convex.  Actually I know that the trace of a symmetric positive definite matrix $S\in M_{m,m}$ is convex since we can find $B\in M_{n,m}$ such that $S=B^T\times B$ then we can write the trace as the sum of scalar quadratic forms, i.e. $\mathrm{trace}(S)=\mathrm{trace}(B^T\times B)=\sum_{j=1}^mb_j^T\times b_j$ where $b_j$ is the $j^{th}$ column of $B$.  for instance if we have  $trace([\begin{array}{cc} 1 &amp; 2  \\ 3 &amp; 4  \\ \end{array}] \times [\begin{array}{cc} 1 &amp; 3  \\ 2 &amp; 4  \\ \end{array}])= [\begin{array}{cc} 1 &amp; 2  \\ \end{array}]\times [\begin{array}{c} 1   \\ 2   \\ \end{array}]+ [\begin{array}{cc} 3 &amp; 4  \\ \end{array}]\times [\begin{array}{c} 3   \\ 4   \\ \end{array}]=30$  And so I wonder if $\mathrm{trace}(S^{-1})$ is convex too.. In C++, sizeof('a') == sizeof(char) == 1. This makes intuitive sense, since 'a' is a character literal, and sizeof(char) == 1 as defined by the standard.  In C however, sizeof('a') == sizeof(int). That is, it appears that C character literals are actually integers. Does anyone know why? I can find plenty of mentions of this C quirk but no explanation for why it exists. I have the following problem: Let $(M, \omega)$ be a symplectic manifold. How can I show $$\omega^n=\underbrace{\omega\wedge \ldots\wedge \omega}_{n-times},$$ satisfies $\omega^n(p)\neq 0$ for all $p\in M$. I believe that is not too dificult but I'm not used with exterior product.. Any help will be valuable...  This is important because the nondegeneracy condition on $ω$ is equivalent to the condition that M has an even dimension $2n$ and the top wedge product $\omega^n$ is nowhere vanishing on M, i.e., $ω^n$ is a volume form. In particular, $M$ must be orientable and is canonically oriented by $\omega^n$. What is the difference between Ubuntu and its derivatives? What different Ubuntu derivatives are there? And what is special with them? Prove: $\displaystyle\sum_{k=1}^n k k!=(n+1)!-1$ (preferably combinatorially)   It's pretty easy to think of a story for the RHS: arrange $n+1$ people in a row and remove the the option of everyone arranged to height from shortest to highest, but it doesn't hold up for the LHS.   Alternatively, trying to visualize the LHS, I noticed that it's like a right angle tetrahedra:  1  2!+2!  3!+3!+3!  ...  But it doesn't help to see a connection to the RHS.  Note: no integrals or gamma function nor use of other identities without proving them nor generating functions. I have answered 'No' to Siri initial prompt, but I can still see it in my process list. I've tried to kill it, but it loads again immediately. How can I unload and remove Siri from my Mac? I have Ubuntu 16.04 with GNOME shell. I set ctrl+shift for the "Modifiers-only switch to next source" option.   This shortcut conflicts with apps hot-keys. I can't use ctrl+shift+i to open devtools in Chrome, it just switches the layout. In VS code IDE if I press shortcuts with ctrl+shift (for example ctrl+shift+f), shortcuts work but always switch a keyboard layout. When I used Windows this problem didn't exist.  Can I set the ctrl+shift shortcut in such a way that it causes a switch action only after the keys are released and only if this 2 keys were pressed (without additional keys)?