Error Propagation: Why using derivatives instead of the function
Why is propagation of uncertainties quadratic rather than linear?
Opening document library files in popup or new window Is there any easy way to open the document library files in a new window or popup depending on the file types?  e.g. PDF - In Adobe reader (currently opens in IE)  Image file (currently opens in IE) Which fruits and vegetables should be kept in a fridge, and which outside? Why can't you use a single resistor for a number of LEDs in parallel instead of one each? How can I test for POSIX compliance of shell scripts? Considering that POSIX is the closest thing to a common standard among all unices, I'm interested in knowing if there's a shell that supports it exclusively. While most modern shells provide support for POSIX (and will run POSIX compliant scripts without any problem), they don't do a good job at pointing out non compliant features.  Is there any shell that implements POSIX and POSIX only, in such a way that it'd throw an error for any non compliant feature?  EDIT I want to clarify that I'm not asking for general tips for writing portable shell scripts. The related question mentionned in the comments already covered this. I thought of this question when I found out that bash has a --posix option but only to discover that it only affects some intialization behaviors which is not exactly what I'm looking for. Accessing Reduce from DSolve Star vs Heart icon to represent save as a favourite I am working on a mobile app that involves the user saving a favourite location. I wanted to use an icon to represent that feature, but I'm not sure which one is better – a star or a heart icon.  Some say heart icon tends to increase the rate of productivity, and some say they are used to a star icon to 'save' or 'bookmark' something.  What do go you guys think? What is the best way to give a C# auto-property an initial value? Evaluate $\lim_{x \to 0} (x\lfloor\frac{1}{x}\rfloor)$  I'm trying to solve it by using the squeeze theorem but I'm stuck.  I'm looking for a function $g(x)$ such that $g(x) \leq x\lfloor\frac{1}{x}\rfloor \leq x(\frac{1}{x}) = 1$  Can anybody give me a hint? How can I make a list with most used commands in terminal? Math mode accents In my long document I, sadly, have to use several accents to denote different kinds of symbols. Currently, I use primes ($x'$), hat, tilde, and overline. In addition I use two colored symbols (red colored tilde and blue $\prescript\ulcorner$), as I need further distinguishment.  Now I'd like to have no colors in my document, while I still have at least six different ways to differentiate certain symbols.  Which alternatives could I use that are easy to recognize and 'stand out', while they are different to prime/hat/tilde/overline?  EDIT: The reader should be able to see the kind of accent used even if the symbol in question is in a sub-script (possibly even a sub-sub-script). Career Change in to Testing I've around 10+ years of experience in Banking operations including  reconciliations, sales, customer services, asset management, and financial transaction QA.  Coming to academics I've done my PG in commerce (costing, auditing, banking, and statistics) also a diploma in project management, ISTQB foundation, Prince 2 foundation and ITIL foundation.    Can any one advise me if the testing role is ideal for me and how to start with it. When I double-click on a script in Nautilus in order to run it, the script opens in my text editor with no option to do so.  Using Nautilus, how do I run executable text files and/or scripts? Directing Domain to Hosting Directory I just purchased a domain on Dreamhost, let's say foo.com. I already have hosting, let's say at 123.4.56.789, and have setup a directory foo.com which is accessible at 123.4.56.789/foo.com/. I can set the DNS to point foo.com to that IP, but how do I route it to that folder once it's there? My hosting has a really bad cPanel that gives me almost no help. Can I use .htaccess, or something else? What's the best way to accomplish this?  Edit in response to comment(s): It's VPS hosting, so I have access to http.conf and other system files. Also, yes it's Apache. Should I buy an original manufacturer battery, or is a generic brand OK? I need another LP-E5 type battery for my Canon 450D. Should I buy an original Canon battery or one of the many generic brands available? There are loads of cheapos on , for example.  I should add that the new battery will be added to my existing Canon battery in a battery grip.  Does anyone have any experience (good or bad) of using generic batteries? How can I handle autocorrelated residuals? In the Breusch-Godfrey test we use a model  $$ e_t = \varepsilon_t + \beta_1 \varepsilon_{t-1} + \dots+ \beta_p \varepsilon_{t-p}. $$  If we reject the null hypotesis of no serial auotocorrelation of the error, it means that the residuals follow an auto-regressive model of order ($p$).  If I want to avoid this problem, I must add a certain number of lags of the response variable $y$ as regressors in the original model. However, in some cases this method is not useful.   Are there other options to consider? I'm trying to install  in VirtualBox but the installation get stuck at Do you want to install boot loader GRUB    Some background:   The VM was created from the Ubuntu 32-bit (x86) VirtualBox template The VM has 1 core + 3096 MB RAM Video memory: 32 MB PAE/NX enabled Hardware virtualization: both VTx and nested pagination enabled Graphics acceleration: disabled (both 2D and 3D) Storage: 64 GB attached to IDE virtual controller (was SATA before: makes no difference)   I've already tried all the "standard" VirtualBox procedure (PAE yes/no; SATA/IDE; no soundcard; no USB; graphics accel. yes/no).  I also tried run the Live CD in VESA mode: like this it starts, but I'd still prefer to install it. accounting for LED resistance Singular or plural verb after a series connected by "or" The following sentence refers to an apocalyptic story where money no longer has any value:     A can of sardines, radio batteries, or a bicycle is/are more precious than money.   Should I use is or are after the series? Run PHPUnit Tests in Certain Order Is there a way to get the tests inside of a TestCase to run in a certain order? For example, I want to separate the life cycle of an object from creation to use to destruction but I need to make sure that the object is set up first before I run the other tests. I'm not sure which of the following sentences is correct. Is the comma mandatory, optional or unnecessary? I've googled a bit about this topic, but I got confused.     Our mapping contains 2000 words, which map to more than one lemma.   or     Our mapping contains 2000 words which map to more than one lemma.   Context: In total, there are more than 2000 words.  I've read  . If I understand the answers correctly, my "which map to more than one lemma" is a defining clause and no comma is required. But is it wrong to add one?