How it is possible to initialize an array in this form with null values? (Java)
What is the difference between an int and an Integer in Java and C#?
Adding curved features to map with ArcGIS API for JavaScript? I've tried without much success to add a curved line feature to the ArcGIS JavaScript map.    I created a polygon with a curved edge in ArcMap:   However, when I load this same feature in the web API, it becomes segmented:   The problem started when I tried to create a curved feature from the JavaScript API itself, which only seems to allow full circle features (not circular arcs).  This makes me think that curves are still unsupported in the JavaScript API. Do you know any way around this? Do you have any other ideas on alternatives I can use to create and correctly view curved features? How do I use a C# keyword as a property name? Using asp.net MVC I'd like to do this inside a view:  &lt;%= Html.TextBox("textbox1", null, new { class="class1" }) %&gt;   This statement does not compile because class is keyword in C#. I'd like to know how I can escape the property names such that this compiles.  It is possible to get this to compile if I change the "class" property to "Class" (uppercase C). But this is not suitable because strict xhtml says that all attributes (and element) names must be lowercase. How to ignore spaces before footnotes I am superimposing CGI over video footage, and have run into a problem in making materials for objects that act as 'shadow catchers'.  Essentially I want a shader that is shadeless—like an emitter—but catches shadows and light from other objects. This is so I can reconstruct objects in footage so other objects in the scene interact convincingly with them.  Here's an overcomplicated diagram to illustrate my point:   (In this particular scenario, the problem could be glossed over by using RGB curves, but that is definitely not the case with more complicated scenes)  Isn't this a common situation? How to the real guys do it? Thank you.  (I am welcome suggestions of other ways of doing this.) Why do not we ask negative questions without a contraction on the not after the verb? I have found multiple questions touching on this but not a single one that has a comprehensive answer. The information is all there but in little bits.     etc.   Exactly why is "Do not you sleep?" ungrammatical (except in poetry/with artistic license)? I understand that not can't contract after you: "Do you not sleep?" because not can only contract after a verb, and that it always does after do: "Don't you sleep?" but why does it (why must it) contract if it's placed after the verb in a question?   Don't you sleep? (common form) Do not you sleep? (ungrammatical) Do you not sleep? (less common form) How to populate the geometry column in a PostGIS table? After loading a polygon shapefile into PostGIS, the geometry column (geom) is blank for several features. In one case, only a single feature has the geometry calculated and all others are blank. I'm using the PostGIS SHP and DBF loader v.2.0. I am creating a spatial index, and using COPY rather than INSERT. I have loaded several other point datasets and they geom column is populated just fine... (Otherwise, things are working just fine for the polygons: when I create a new feature, the geometry is calculated / geom field populated...etc.) Have I done something wrong when importing the data?  Solution by @ThomasG77 (in comments) PgAdmin3 [doesn't] display features that are too complex but they are present.  You can try SELECT length(ST_astext(the_geom)) from your_table to confirm or you can find &quot;true&quot; empty geometry with SELECT * from your_table WHERE the_geom IS NULL;. Show that if $ R $ is an integral domain then a polynomial in $ R[X] $ of degree $ d $ can have at most $ d $ roots Show that if $ R $ is an integral domain then a polynomial in $ R[X] $ of degree $ d $ can have at most $ d  $ roots.  Thoughts so far:  I feel like I might be missing something here. If $ R $ is an integral domain, then so is $ R[X] $. The factor theorem gives a correspondence between roots and factors. Clearly (is this clear?) a polynomial of degree $ d $ can't have more than $ d $ irreducible factors. primitive n-th roots of unity Show that the primitive n-th roots of unity have the form $e^{2ki\pi/n}$ for $k,n$ coprime for $0\leq k\leq n$.  Since all primitive n-th roots of unity are n-th roots of unity by definition they all have that form, the question is, how to show $k$ and $n$ are coprime. Show that a ring is commutative if it has the property that ab = ca implies b = c when $a\neq 0$ Show that a ring is commutative if it has the property that ab = ca implies b = c when $a\neq 0$.   This is my proof to show that a ring is commutative if it has the property that ab = ca implies b = c.  We need to show that if x, y ∈ R then xy = yx. Let a = x, b = yx and c = xy. Then ab = x(yx) = (xy)x = ca. Thus, by the hypothesis, b = c, or xy = yx. Thus, for x, y ∈ R we have xy = yx.   How would I show when $a\neq 0$? Advanced format partition alignment I cloned a non Advanced Format drive (W7 64bit) to a new hard drive (Seagate) that was AF, the software I used supposedly does not support 4k very well (Todo Backup Free 3.5).   Is there a Windows utility to check alignment? I know of the Western Digital tool but not sure if it works on Seagate brand drives. If the partitions are not aligned, Am I better to clean install W7 64bit or do the partition alignment procedure? If so, Why?   It seems to be running fine so far. From what I have read Seagate drives use  technology to help with misaligned partitions on the fly, might explain why it runs well for me, but would still like to have the partitions aligned properly.  EDIT: Here is the diskpart output for my disk partitions  DISKPART&gt; list partition    Partition ###  Type              Size     Offset   -------------  ----------------  -------  -------   Partition 1    Primary            188 MB    31 KB    Partition 2    Primary            698 GB   188 MB How can I copy a custom Dictionary on Word 2000? Given that , I wonder if every intelligent biological species is capable of producing beings that are Force-Sensitive?   Or are there some species characteristics that can make it 100% impossible for them ever to produce a Force-sensitive individual.  NOTE: Let's exclude - if they exist in EU - things like random new-species-creating mutations - e.g. the individual should be 100% the same species, able to interbreed. How to know when to change a chain? A bike shop employee used a tool he said would check the wear on the chain, and said that it should be changed.   He said it took a measurement that meant the chain had expanded, but it is still hard for me understand why I should change the chain.   He said that the reason was that the expanded chain links will cause the chain rings to wear down.   That is one argument and I have no experience with it, to know if it is true.   But are there more reasons? How do I know when the chain should be changed?   My first thought is to use it until it breaks, but it probably is not the wisest option. Why does the SARS-CoV2 virus not remain infectious forever? Or does it? Given that the majority of biologists do not currently consider viruses to be alive, a virus can never die.  It can, however, get destroyed by long exposures to soapy water, alcohol, and apparently certain frequencies of UV light.  Why is an individual SARS-CoV2 virion not infectious forever?  Or is it? Understanding complete separation for logistic regression Why does logistic regression not converge for a linearly separable data set?   For linear separable data sets the model parameters go to infinity when mimizing the error function (according to Bishop2006, Pattern recognition and machine learning, section 4.3.2). I don't understand why. It must be connected to setting the score function, i.e. the derivative of the error function, to zero.  The error function is given by $E(\mathbf{w})$ as shown in the figure below. Where $\mathbf{t}$ is the target variable vector of the training set and $\mathbf{w}$ the parameter / coefficient vector. The posterior probabiltiy for class 1 is given by  $$y(n) = p(C_1|\mathbf{x}_n) = \sigma(\mathbf{w}'\mathbf{x}_n).$$ Where sigma is the logistic sigmoid function and $\mathbf{x}_n$ is the feature vector for instance $n$ including the predictors.     My second question to logistic regression is if the to posterior probabilities $p(C_1|\mathbf{x}_n)$ and $p(C_2|\mathbf{x}_n)$ sum to one? Why do I get a black rectangle instead of my external picture? I write some of my network notes in TeX. I wanted to make a table, and inside it insert an image:   .   I wrote a document:  \documentclass{article} \usepackage[demo]{graphicx} \usepackage{booktabs} \usepackage{array}  \begin{document} \begin{tabular}{m{3cm}m{3cm}m{5cm}} \toprule Configuration for ... &amp; Commands &amp; Topology\\ \midrule PPP: CHAP, PAP &amp; \#sh int se 0/0/0  &amp; \includegraphics[width=4cm, height=4cm]{chappap.png}\\  &amp; &amp; \\ \bottomrule \end{tabular} \end{document}   But instead of my network topology image, I see only this: .   I don't know what is wrong, cause my image is 100% in the same dir, as my *.tex file.  EDIT:  Changed my code as @Jubobs suggested, now everything is as I wanted:  \documentclass{article}     \usepackage{graphicx}     \usepackage{booktabs}     \usepackage{array}      \begin{document}     \begin{tabular}{m{3cm}m{3cm}m{5cm}}     \toprule     Configuration for ... &amp; Commands &amp; Topology\\     \midrule     PPP: CHAP, PAP &amp; \#sh int se 0/0/0  &amp; \includegraphics[width=4cm, height=4cm]{chappap.png}\\      &amp; &amp; \\     \bottomrule     \end{tabular}     \end{document} How to convert milliseconds into human readable form? I need to convert an arbitrary amount of milliseconds into Days, Hours, Minutes Second.  For example: 10 Days, 5 hours, 13 minutes, 1 second. How to reset Canon 70D WiFi? Indexing redundantly named vector in R Evaluating $\int P(\sin x, \cos x) \text{d}x$ Suppose $\displaystyle P(x,y)$ a polynomial in the variables $x,y$.   For example, $\displaystyle x^4$ or $\displaystyle x^3y^2 + 3xy + 1$.  Is there a general method which allows us to evaluate the indefinite integral     $$ \int P(\sin x, \cos x) \text{d} x$$   What about the case when $\displaystyle P(x,y)$ is a rational function (i.e. a ratio of two polynomials)?   Example of a rational function: $\displaystyle \frac{x^2y + y^3}{x+y}$.    This is being asked in an effort to cut down on duplicates, see here:   and here: