What's wrong with these equations?
A proof that $1=2$. May I know why it’s false?
I've looked at the demo of Beeline reader and would like to test it out on a physical version of my books, which are done in LaTeX. I'm wondering if it would even be possible.   Beeline reader takes online test a puts a slight gradient on the letters for a single line of text. On the next line it reverses the direction of the gradient. The idea being that it helps tracking text and improves speed of reading.  Any hints or suggestions as to how to do this in LaTeX?  What follows is an example taken from Punctuation with units I remember reading somewhere that if a unit is abbreviated as one character, there must not be a space between the number and the unit (e.g., 5m, 26K). If the unit is abbreviated as two or more Characters, there must be a space between the number and the unit (e.g., "10 km", "USD 5").   Can you please help me find the source again? Is this recommendation correct? Make the network profile editable on the main Stack Exchange page Currently, the Stack Exchange Network Profile links to all the network accounts and acts as a centralized profile page. Seeing that the ability to edit the profile is available from the profile pages of all *.SE sites, I think the ability to edit profiles should be available on that Network Profile page as well.  It will be consistent with the nature of the centralized profile page and will better the user experience.   EDIT: As the current Network profile, is actually the oldest profile on the Network, providing an edit option on the Network profile which links to the oldest profile edit page, would be one way to implement this. I was curious about how other people use the this keyword. I tend to use it in constructors, but I may also use it throughout the class in other methods. Some examples:  In a constructor:  public Light(Vector v) {     this.dir = new Vector(v); }   Elsewhere  public void SomeMethod() {     Vector vec = new Vector();     double d = (vec * vec) - (this.radius * this.radius); } Top-bar hat misplaced A while ago I upgraded from Ubuntu 17.04 to Ubuntu 17.10 and everything is working fine except for the fact that the icon in the window title bar of my Terminal seems to be stretched out to some ridiculous size.    This only seems to happen in the Terminal window. The Nautilus icon is completely fine.    The problem seems to go away if I login into an Xorg session instead of a Wayland one. I've looked around and didn't find any immediate solution to this. Any help would be greatly appreciated. Default poster size What is the typical size for a conference poster? Is it "ask the organizers", or can I safely assume that I'll get a default size, and that there will be enough space to hang it at the poster session? Possible Duplicate:          I have been downvoted for few answers of mine and the person who downvoted me did not leave any comments or reasons to say why I was downvoted. In such cases, how can I find out who has downvoted me and the reason for downvoting? Can't flag or close questions on all sites Whenever I try to flag or close a question here, when clicking the submit button the button gets disabled, three dots animating and nothing really happens.  JS console show a single error:  Flagging:     Uncaught TypeError: Cannot read property 'flagSubmitting' of undefined    Closing:     Uncaught TypeError: Cannot read property 'closeSubmitting' of undefined   Please fix, programming questions and spam are beginning to pile up. :(  Update: appears to work fine from within the review system, but otherwise it's the same on Stack Overflow as well join comma delimited data column What's so special about standard deviation? How to overlay images I want to overlay one image with another using CSS. An example of this is the first image (the background if you like) will be a thumbnail link of a product, with the link opening a lightbox / popup showing a larger version of the image.   On top of this linked image I would like an image of a magnifying glass, to show people that the image can be clicked to enlarge it (apparently this isn't obvious without the magnifying glass). How can I convert string to datetime with format specification in JavaScript? Is there a easy way to test ubuntu on new notebooks before buying it? Completing a 3x3 correlation matrix: two coefficients of the three given I was asked this question in an interview.  Lets say we have a correlation matrix of the form \begin{bmatrix}1&amp;0.6&amp;0.8\\0.6&amp;1&amp;\gamma\\0.8&amp;\gamma&amp;1\end{bmatrix}  I was asked to find the value of gamma, given this correlation matrix. I thought I could do something with the eigenvalues, since they should be all greater than or equal to 0.(Matrix should be positive semidefinite) - but I don't think this approach will yield the answer. I am missing a trick.  Could you please provide a hint to solve for the same? How to specify font size less than 10pt (or more than 12pt)? Related:  (not a dupe, that's a feature request and was closed as a dupe of another one)        (old) post does indeed say that Link-only answers can be flagged as NAA, but there are a lot of posts like  which define Not An Answer is a way that it doesn't apply to link-only answers.  Can we get some up-to-date consensus on this? That link only answers are not allowed is . This dreaded issue started at some time after upgrade to OS X (Yosemite) 10.10.3. accountsd uses about 60% CPU constantly, making the laptop hot and noisy.  I'm not using iCloud at all.  Killing it doesn't help, because it starts again quickly.  Probably related question, but it's about iOS: List all my drafts In GMAIL you can list all your boss-tell-off and wife-cuss-out emails by clicking Drafts    I'd like to see my started-but-never-finished responses, possibly between x Answers and y Votes in /&lt;&lt;user&gt;&gt;/Stats/? Sed - unknown option to `s'