What is the simplest and best way to determine if the browser is IE or not?
How to detect Safari, Chrome, IE, Firefox and Opera browser?
A case of optional “that”: “check the” vs. “check that the” Consider the following use case:   Please check the username and password are correct. Please check that the username and password are correct.   In this case, I would say that that is required because it feels more natural to me and so the flow is better. However, is the lack of that wrong in this case?  The question boils down to: when is that optional? See . A quick summary:   That is optional if the pronoun is the object. That is required if the pronoun is the subject.   I think that we fall into the second case: that is required because the relative pronoun is the subject. But I'm not sure if I'm interpreting these rules correctly. Can someone please advise? Every separable Banach space is isomorphic to $\ell_1/A$ for some closed $A\subset \ell_1$ How to prove the following mind-blowing fact?     Let $X$ be a separable Banach space and let $\ell_1$ be the space of all absolutely summable scalar sequences. Then there exists such closed subspace $A\subset \ell_1$ that factor space $\ell_1/A$ and $X$ are isomorphic as normed spaces.   Edit: So what, this is like a classification up to isomorphism of all separable Banach spaces? Each separable Banach space corresponds to some closed subspace of $\ell_1$? Get last n lines of a file, similar to tail I'm writing a log file viewer for a web application and for that I want to paginate through the lines of the log file.  The items in the file are line based with the newest item at the bottom. So I need a tail() method that can read n lines from the bottom and support an offset.  This is hat I came up with: def tail(f, n, offset=0):     &quot;&quot;&quot;Reads a n lines from f with an offset of offset lines.&quot;&quot;&quot;     avg_line_length = 74     to_read = n + offset     while 1:         try:             f.seek(-(avg_line_length * to_read), 2)         except IOError:             # woops.  apparently file is smaller than what we want             # to step back, go to the beginning instead             f.seek(0)         pos = f.tell()         lines = f.read().splitlines()         if len(lines) &gt;= to_read or pos == 0:             return lines[-to_read:offset and -offset or None]         avg_line_length *= 1.3  Is this a reasonable approach?  What is the recommended way to tail log files with offsets? $f: \mathbb{R} \to \mathbb{R}$ that takes each value in $\mathbb{R}$ twice Does there exist a continuous function $f: \mathbb{R} \to \mathbb{R}$ that takes each value in $\mathbb{R}$ exactly two times? I have a subomain which I do not want to be listed in any search engine result. Let say I have:   http://www.example.com http://child.example.com   How can I hide all URLs of child.example.com domain which are currently showing in the search engine results? I have a problem , i can't open synaptic >:(  root@dopeboy:~# synaptic No protocol specified ** (synaptic:6940): WARNING **: Could not open X display No protocol specified (synaptic:6940): Gtk-WARNING **: cannot open display: :1   I have try to Re-install it but is not working, any idea how to fix?! VPS Ubuntu 14.04 LTS. I've a Skype interview for PhD application (it will make me miss  today.) I've been asked, in advance, to prepare a short presentation and then there would be some discussion with the panel (I guess.) I expect that they will ask if I have some questions so, I'm wondering what are the best (type of) questions one might consider? What is the right way to get the current users profile in an apex class?  When I tried to print the following in visualforce page,  i am able to get the profile name  &lt;apex:outputText value="{!$Profile.Name}"/&gt;    But when i tried to print in the Apex class using System.debug(Profile.Name), I couldn't. Multiple object instances represented by two slightly shifted rectangles In a software diagram, I'd like to be able to represent multiple instances of an object by two rectangles with one of them slightly shifted. I recently learned about the pic style so I'm using it with two nodes to achieve what I want.  The following example does work, but I'd like to know if I can do the same without using the fill=white. My hack kind of assumes the entire picture background is white and that may not always hold. I'd like to be able to crop the unwanted picture part out.  \documentclass[crop,border=3pt]{standalone}  \usepackage{pgf,tikz} \usetikzlibrary{positioning}  \begin{document} \begin{tikzpicture}[     every node/.style={font=\sffamily\small},     block/.style={         rectangle, draw, align=center, minimum width=2cm,         minimum height=1.4cm, font=\sffamily\small     },     multinode/.pic={         \node [block] at (0.1,0.1) {};         \node [block, \tikzpictextoptions, fill=white] at (0,0) {\tikzpictext};% &lt;-- FILL WHITE     } ]     \node [block] (STG) at (2,5) {single\\instance};     \pic [pic text={multi\\instance}] at (5,5) {multinode}; \end{tikzpicture} \end{document}   The following images show first one version with the fill white hack, and then one version without it. Variation of Pythagorean triplets: $x^2+y^2 = z^3$ Saudi Arabia Transit Visa I am travelling to Rome along with five other members (all in a family) from Bengaluru via Jeddah. My layover in Jeddah is 13.5 hours before i catch a connecting Flight to Rome. I won't be moving out of airport in Jeddah. Do I still need a Transit visa in Saudi Arabia. CPU on Ubuntu running high In the terminal I used "top" to check the processes and how much of the CPU was being used as I thought max was 100%, so I restored 292,000 photos with recoverjpeg on my sda1 HDD, I opened the folder and the Nautalis is  fluctuating between 130% and 170% , should I close the program and am I at risk of my gpu locking up ? How to use "who" vs. "that" I often get confused when trying to use who vs that.  Some examples that often confuse me:  That     The person that went to the store.      The people that went shopping.      The persons that went shopping.      The group that went shopping.   Who     The person who went to the store.      The people who go shopping.   Please explain when to use either for plural subjects and singular subjects.  Animate and inanimate objects as well. How to find and replace in linux on a large file? Oh, hi; So I've got this big json file and I'm trying to find and replace a few things but when I've used sed I get an error and I need a sed or awk string to find and replace it, without getting an error.  prajwal  Current: {&quot;telephone_numbers&quot;:[&quot;1-  Future: {&quot;telephone_numbers&quot;:[&quot;+1-  This is the command i tried and the error i got. sed -i 's/{&quot;telephone_numbers&quot;:[&quot;1-/{&quot;telephone_numbers&quot;:[&quot;+1-/g' output.json sed: -e expression #1, char 56: unterminated `s' command Alright, so the idea of an exponent, $x$, is that you are multiplying its base by itself $x$ number of times. With base $5$ and $x=3$, we have that $5^3$ = $5 \cdot 5 \cdot 5$  I understand that the logarithm with base $a$ of $x = c$,  tells us that  $$a^c = x$$  and for $c =$ positive; values for $x$ are greater than $1$, and for $c =$ negative; values for $x$ are less than $1$,  and for $c = 0$, values for $x$ are...$1$.  So in short, I understand how, by means of observation of the graph of $f(x) = \log x$, we can see that $f(1) = 0$, BUT, I see no other way to understand why $x^0 = 1$, apart from the graph and everything around that very point.  I honestly cannot get my head around the idea, "$5$ times itself $0$ times... is one".  Is it that there is no fundamental answer for this but that we simply know by the graph? Or can I truly understand $x^0 = 1$ on its own? Geometric proof that a Pythagorean triple has a number divisible by $3$? Can I infer from “If $a,b \in \mathbb{N}$ such that $(a,3)=(b,3)=1$ then $a^2+b^2\neq c^2$ for any $c\in\mathbb{N}$” that any pythagorean triple has a number which is divisible by $3$? If so, how can this relationship be proved geometrically? I saw a video where the person copied a material from one object to another (Cycles).  How can I accomplish this? Is $0 \, \mathrm m = 0 \, \mathrm s = 0 \,\mathrm {kg} = 0$? How do we define $[0 \, \mathrm m]$?  I once was given an assignment where I was asked to deduce and write down some physical quantity. It turned out that this quantity was $0$ in one unit or another, so I decided to drop the physical units because I figured that it didn't matter anyhow.  But I got to thinking:  If $0 \, \mathrm m = 0$, then we could add units of different dimensions (an operation not normally defined) like so: $5 + 0 \,\mathrm m = 5$.   Does $[ \cdot ]$ map $0 \, \mathrm m$ to both $0$ and $L$? Is there an established regime of thinking about physical quantities as an abstract algebra? Perhaps as a vector space where formal sums such as $5 \, \mathrm m + 10 \, \mathrm s$ are allowed? Would it be improper to drop the units of measurement of $0 \,\mathrm m$ like this in an academic paper? Strictly increasing sequence $\{ a_k \}$ of positive integers such that $\sum 1/{a_k}$ is finite If electrons were positive and protons were negative, would life be different? This was a question on a worksheet during my first week in a class on Electromagnetism. The answer is essentially:     No. Life would be no different if electrons were positively charged and protons were negatively charged. Opposite charges would still attract, and like charges would still repel. The designation of charges as positive and negative is merely a definition.   But how would we have negative charges within the nucleus? Taking a look at the , it seems that down quarks are required in this new "negative proton" to help with creating the pion to "transmit a residual part of the strong force even between colorless hadrons".  I tried to set out and try to find a particle with (-1) charge with a down quark (by going through this ) but all the particles are not stable with the exception of two unknown:   Bottom Xi Baryon Double Bottom Xi Baryon   Assuming one of the above are stable, could the strong force act between one of them and a neutron, implying its alright to have a negatively charged nucleus?  Edit: If it wasn't clear, my question concerned whether or not there existed stable baryons of $-1$ charge with down quarks that could "replace" the proton.