What's the proof of the light polarization that it happens to the electric field and not the magnetic field? How did Malus discover that the light is polarized although he didn't see the waves polarizing!
If the magnetic field doesn't polarize does it follow the electric field path of propagation? or does it vanish?
How to make a process invisible to other users? How could you launch a process and make it invisible to the top command? The process is started by a normal user (not root), and should not be visible to other normal users. Minecraft launcher could not connect to server? What do I do? I looked at a similar question to mine and there was an answer saying to make sure Java is allowed past the firewall. So I checked and it already is. I've tried uninstalling and installing both Minecraft and Java but nothing has changed.  says that all services are fine, so what's going on? I bought a 2nd account to use as an alternative in-game account and now I can't log in.  (I cleared the email and password boxes for obvious reasons in this screenshot: security purposes) If $$\tan(\frac{\pi}{4}+\frac{\theta}{2})=\tan^3(\frac{\pi}{4}+\frac{\alpha}{2})$$, then prove that $$\sin \theta=\frac{3 \sin \alpha+\sin^3 \alpha}{1+3\sin^2 \alpha}$$  I tried using the fact that  $\frac{\cos A}{1-\sin A}=\tan(\frac{\pi}{4}+\frac{A}{2})$ but now not able to eliminate $\cos \alpha$ and $\cos \theta$. How should I proceed? Does either pill actually do anything? When Morpheus offers the pill choice to Neo, they are still in the Matrix. That leads me to belive that none of the pills are real thus having no particular effect in the real world. Was it some sort of placebo effect that freed Neo from the Matrix or do the pills have an actual effect? Prove $|\arctan x - \arctan y|\leq |x-y|$ Mysterious cord running from wall. Safe? My wife and I are preparing to sell our home and are discovering some weird things. Our home was built in 1958, so it is older. We found this in a corner that had some furniture in front of it.   We are wondering    What kind of wiring is this?  Is it safe to handle or remove? Why isn't the eigenclass equivalent to self.class, when it looks so similar? Invalid group name: Group names must begin with a word character I received the following exception when I was using the Regex class with the regular expression: (?'named a'asdf)  System.ArgumentException: parsing \"(?'named a'asdf)\" - Invalid group name: Group names must begin with a word character.   What is the problem with my regular expression? Plot Summary/Details  A human spacecraft lands on an alien world.  I'm not sure if they are exploring, or touched down for repairs. The world is a foreboding place, and home to a vicious predator that somewhat resembles a panther, or other big terrestrial cat. The creature is quite cunning, and ambushes several crewmen when they are scouting the planet or doing some other activity that would have them isolated and away from the ship. It sticks in my mind the creature is very strong, and able to bite through the heavy spacesuits the men wear with ease.  The creature has an unusual nutritional requirement of some sort. As such, it doesn't eat its victims, but somehow drains them of a particular element or chemical substance. I can't remember what it is, though I think it had something to do with the skeletal structure of the men. Calcium, maybe?  I have only very general recollections of how the story ends/is resolved. The humans become aware of the threat, and I believe they ultimately slay the beast. I can't recall anything more specific than that, unfortunately.  Timeframe of Publication  This one is old, I'm sure of that. I can remember the writing style and some of the descriptions being very "old school" - spacemen, rocketship, that sort of thing. Almost like something you'd see in an old sci-fi movie serial, to use a film analogy. If I had to guess, I'd say 1950's at the latest. In response to  question, I started to think about what it means when a Wild Magic Surge results in a "You cast spell-X".  So, "specific beats general" gives:   You can cast a second spell when you would not normally be allowed to You can cast a spell you don't know If the surge forces you to cast a concentration spell you would lose any concentration spell that you currently had active Subject to what the specific entry says you can target it how you like Unless the specific entry prohibits it you could use metamagic on the spell   I am pretty confident in all of the above but if anyone disagrees please address in an answer.  Here comes the question.  How does this impact on your available spell slots?  "You cast ..." to me suggests that if you have an applicable slot available then you have to use it to cast the spell because that is the general rule for casting spells but if you don't then "specific beats general" and it is cast anyway.  Specific examples:     You cast fireball as a 3rd-level spell centered on   yourself   This must be a 3rd level spell:   if you have a 3rd level slot available you have to use it? if you don't, if you have 5 sorcery points and a bonus action available must you use these to get that slot? if you don't have any of that then the spell goes off anyway?      You cast confusion centered on yourself.   No level specified and confusion is a 4th level spell:   if you have a 4th level slot available you have to use it? if you have a 4th, a 6th and an 8th level slot you can choose which one to use? if you have only a 5th level slot but also 6 sorcery points and a bonus action, you could choose to use the 5th level slot or use the points to create a 4th level slot? if you don't have any 4th level or higher slots but you have 6 sorcery points and a bonus action available must you use these to get that slot? if you don't have any of that then the spell goes off anyway?   And so on ... Automatically convert links to popular mobile pages (such as the mobile Wikipedia) to point to the corresponding regular pages This issue came up  on Worldbuilding:  If somebody is on a mobile device and wants to cite, e.g., Wikipedia, they usually insert a link to the  instead of the regular one. This is annoying for users with immobile devices, while it poses no benefit to users with mobile devices, who should get redirected to the mobile Wikipedia anyway.  I thus request that links to mobile versions of popular web pages are automatically converted to regular ones either in the post source or when rendering the page.  As  mentioned, an author may sometimes explicitly want to link to the mobile version of a webpage but as far as I can tell, this should be the exception. At least for Wikipedia, an automatic conversion would do much more good than harm, because it is very often cited as a resource. For example, until recently, there were at least 82 posts with links to the mobile Wikipedia on Worldbuilding alone (going by  edit spree to remove them) Visiting Greece with back-to-back Schengen visas (One from Germany, other from Italy) I have a Schengen Visa issued by Germany, which expire on 11th Jan 2014, and I can remain in the zone till 11th Jan 23.59 PM. I have already visited Germany in the past with this visa, so I can travel whenever in Schengen zone directly from my country (Turkey).  I have a second Schengen Visa issued by Italy, which START on 12th Jan 2014, such that I can remain in Schengen zone from 12th Jan 00.00 AM onwards (I'm putting times to clarify which dates are inclusive).  I would like to travel to Greece with this visa: Entering the country on 6th January, and leaving the country on 19th January.  Is this allowed? Or do I have to leave the country first, and then re-enter through Italy? Can crumbled feta cheese last almost a year? talks about feta cheese in a brine or milk bath lasting up to three months.  What about crumbled feta?  I was looking through the fridge, and found a 1/2 pound open container of crumbled feta.  I have only used about an ounce of it.  There is no sign of mold on it, and it smells like feta cheese.  A small sample tasted okay.  The amazing thing is that I bought it in October or November: 8-10 months ago!  I have a recipe that calls for almost a 1/2 pound of feta, and I will be the only one eating it (so I'm not trying to impress anybody!).  I dislike wasting food, but I dislike being sick even more!  Is it safe to use dry crumbled feta that is so old? Plotting logarithmic regression with gnuplot using PGFPlots I have the data in 001.csv below that I want to plot. I need two plots: one showing the data and another one showing logarithmic regression. I have no problems plotting the line for the data (and also adding a linear regression line) but I just can't manage to get a logarithmic regression line in there. As far as I understand, I need to use gnuplot for this but unfortunately I can't make it work. Any help would be much much appreciated.  Cheers,  Cem  %%%%%%%%%%%%%%%%%%%%%% %This is my data:  \begin{filecontents}{001.csv}     1990 275     1991 187     1992 249     1993 177     1994 212     1995 303     1996 323     1997 364     1998 461     1999 427     2000 683     2001 553     2002 571     2003 682     2004 585     2005 608     2006 609     2007 643     2008 719     2009 545 \end{filecontents}  %%%%%%%%%%%%%%%%%%%%%% %This is my plot for the data:  \begin{tikzpicture} \begin{axis}[     axis on top=false, axis x line=middle, axis y line=middle,     xlabel={\footnotesize Year},     ylabel={\footnotesize Frequency count},     xmin=1975, xmax=2009,     ymin=0, ymax=900,     xtick={1980,1985,1990,1995,2000,2005,2009},     ytick={0,100,200,300,400,500,600,700,800},     legend pos=north east,     legend style={font=\fontsize{6}{5}\selectfont},     ymajorgrids=true,     xmajorgrids=true,     grid style=dashed,     /pgf/number format/.cd,     1000 sep={}     ]  \addplot[     smooth,tension=0.9,color=blue,mark=diamond         ] table {001.csv};  %Somewhere here I need a logarithmic regression line.  \end{axis} \end{tikzpicture}  %%%%%%%%%%%%%%%%%%%%%% How do I make protocol foo hostname-aware? This is a  about hostname-awareness and proxying.   I know that some protocols are hostname-aware; that is, when I connect to the HTTP server at www.example.com it knows I want www.example.com's HTTP service, not www.example.net's, even though they are on the same IP address.  How can I do this for protocol foo?  (Temporary note: this question appears pursuant to .) How to interpret regression coefficients when response was transformed by the 4th root? I'm using fourth root (1/4) power transformation on my response variable, as a result of heteroscedasticity. But now I'm not sure how to interpret my regression coefficients.   I assume that I would need to take the coefficients to the fourth power when I back-transform (see below regression output). All of the variables are in units of dollar in millions, but I would like to know the change in dollar in billions.    While holding the other independent variable constant, a billion dollar change in fees, on average, leads to a change of 32 (or 32,000 dollars) in collections. I take 0.000075223 * 1000 (to get to billions) ^ 4 = 0.000032. Now do I multiply this number by 1 million or 1 billion (the original unit of the dependent variable is in millions)?  lm(formula = (Collections^(1/4)) ~ Fees + DIR)                   Estimate      Std. Error  t value            Pr(&gt;|t|) (Intercept)   2.094573355     0.112292375   18.653  0.0000000000000151 Fees        **0.000075223   **0.000008411    8.943  0.0000000131878713 DIR           0.000022279     0.000004107    5.425  0.0000221138881913 Executing .bat file "within 1 to 2 weeks" vs "in 1 or 2 weeks" Let $x$ and $y$ be integers not congruent to $0$ modulo $p$ where $p$ is a prime. Prove that if $p \equiv 3 \pmod{4}$ then $x^2+y^2 \not \equiv 0 \pmod{p}$.   I thought about proving this algebraically and by contradiction. So we say $x^2+y^2 = pz$ and have to show this is impossible. Loop-cut won't go all the way around Alright so I've seen some postings about loop cuts and done some research. I am very new to blender and modeling overall. I am trying to loop cut this concrete barrier. Now I'm following a tutorial and kind of did my own thing in some areas. I cleaned it up following some instructions in another answer here on stack exchange.  I can't for the life of me figure out why I can loop cut around the whole bottom:   ...but not the whole middle:   I see this marked as answered by another question. That question refers to ngons and inside faces. Now once again I'm totally new to this. I looked on the inside. I don't believe I have inside faces or any ngons by the terms I've read online in my research.  Here is a wireframe picture and the inside view:     Maybe I'm missing something the answers on other posts are saying. If so and you know what it is I'd be very appreciative of what it is.