I have gone through the process of installing the boot for usb drive. The drive had no problems when I went through the process. The problem is when I try to boot from the drive it just goes to the windows boot up.   So I tried disabling the windows drive and only allowing the usb and then what happen was it just keeps going back to the bios menu like there is nothing there.   I am using windows 10 Home 32-bit installed by manufacture, on an asus netbook model X205TA. I tried installing ubuntu 17.04 through the set up that ubuntu provides to put on a usb drive.
How do I make an Bootable Ubuntu USB containing the the latest version of Ubuntu?  For completeness, how would I be able to do this on Ubuntu, Windows, OS X or another Linux distro?
This question is about an efficient way to compute principal components.   Many texts on linear PCA advocate using singular-value decomposition of the casewise data. That is, if we have data $\bf X$ and want to replace the variables (its columns) by principal components, we do SVD: $\bf X=USV'$, singular values (sq. roots of the eigenvalues) occupying the main diagonal of $\bf S$, right eigenvectors $\bf V$ are the orthogonal rotation matrix of axes-variables into axes-components, left eigenvectors $\bf U$ are like $\bf V$, only for cases. We can then compute component values as $ \bf C=XV=US$. Another way to do PCA of variables is via decomposition of $\bf R=X'X$ square matrix (i.e. $\bf R$  correlations or covariances etc., between the variables ). The decomposition may be eigen-decomposition or singular-value decomposition: with square symmetric positive semidefinite matrix, they will give the same result $\bf R=VLV'$ with eigenvalues as the diagonal of $\bf L$, and $\bf V$ as described earlier. Component values will be $\bf C=XV$.   Now, my question: if data $\bf X$ is a big matrix, and number of cases is (which is often a case) much greater than the number of variables, then way (1) is expected to be much slower than way (2), because way (1) applies a quite expensive algorithm (such as SVD) to a big matrix; it computes and stores huge matrix $\bf U$ which we really doesn't need in our case (the PCA of variables). If so, then why so many texbooks seem to advocate or just mention only way (1)? Maybe it is efficient and I'm missing something? What is Stack Overflow's business model? I once , but that was . Now, , and they have , but where's the business model? The  its own Q&amp;A about its site (since it wasn't included in the ), and just about the only dig in there that halfway has merit is the business model dig:  We switched to a premium model to keep out of the Venture Capital business (been there, done that, got the t-shirt). Companies like StackExchange couldn't do it without the VC cookie jar. Where's the model? Huh, Spolsky? (I’m sorry. Did that slip out?)  It hurt, but I can't help but wonder if they're on to something.  How would Stack Overflow Internet Services pay back the VCs? Ad revenue alone?  There is only one 'paid' product, Stack Overflow careers, but it doesn't seem like that could sustain a business as large as Stack Overflow (Joel once mentioned on his blog that his jobs board brought in an extra million a year in revenue). So what does Stack Overflow do when the VC cash runs out? Is this a get-big-and-take-the-company-public maneuver? Is that the only viable business model for Stack Exchange? Edit: With the size of Stack Overflow's team, it isn't a stretch to say that payroll is at least $2 million  a year, probably as much as 4 when you think about benefits (average 120K for a developer in New York City; x2 for benefits/taxes/all-that-other-good-stuff). Office space can't be cheap, so how long does $6 million last before you need another VC infusion? Why is an untranslated string not showing up? In my module I have some custom strings. I use these in the t() function. When I go to admin/config/regional/translate/translate and filter the untranslated strings my custom strings do not show here.  What could be going wrong? Let $\left| {{a_{ii}}} \right| > \sum\limits_{i \ne j} {\left| {{a_{ij}}} \right|} $.Why does $A$ is nonsingular? . Should I sign, watermark or otherwise label a framed print? And if so how? I have an opportunity to show some of my work in a small local coffee shop.  Are there any guidelines/practices to signing, labeling or watermarking a photo which is to be on display?  Or should a photo be signed, labelled or marked at all? Is signing the back of the photo and showing my name on a separate card below the frame itself the "better" way to do this?   I noticed many people on the web put a very noticeable watermark with their logo, copyright and name right on the photo.  Personally, I find this distracting as it often ruins the photograph itself often turning what could be art to kitsch. Painters most often sign the painting itself but this to me is not distracting because it is done with the painter's own hand and it often "works" with the painting. Automating the appearance of email addresses as images Publishing pdf manuscripts on the web with emails embedded in the file results in spam.  More generally, I am looking for a way to automate the conversion of a string to an image.  It's quite easy to solve this old problem using  (more ). The trouble is that you need a distinct file and typesetting run, and you end up with unnecessary image files that you cannot delete carelessly lest you also delete non-generated images.  Can you think of a way to do this on the fly? It's understood that people will have to type the email addresses if they need to message you, but that's the point.  More briefly/concretely...  With what can one replace #1  \documentclass{article} \newcommand\showasimage[1]{#1} \begin{document} \showasimage{joe@foo.bar} \end{document}   such that #1 appears as an image?  Edit  It would be really nice if the pdf file remains vectorial. Shutdown from terminal without entering password? I have desktop edition of Ubuntu.  I like the Terminal so that that I prefer to shutdown my computer with the shutdown command.  However when I type shutdown now it prompts me to enter my password.Is there any way I can shutdown my computer using this command without entering my password? Is there some markup to post tags? I am wondering because I was editing my profile and I though it would be nice to put the languages I know and stuff like tags.  Is it possible to post a tag? If it's not, do you think it's possible to implement on the profile?  For example:  [c#]   Would generate    With tag formatting and link... There is by now a captcha-problem One Time Pad Key Distribution For multiple OTP keys, why not do this:  Key = Hash[(EC)DH Shared Secret + Counter]  The counter will increase per message, and the output of the hash will be random for each new unique input into it. What are the problems or weaknesses with this design??  EDIT: For clarification: both parties will have the shared secret from an ECDH exchange, random numbers from Pythons os.urandom for generating the ECC key How to unmap TAB and do not make Ctrl-I invalid in VIM It is possible to find an efficient algorithm for constructing a provably hard to factor number $N$, together with a witness that shows that it is indeed hard to factor. EDIT, since it was not clear: I also want to be sure that even the person that constructed the number cannot factor it.  Of course, a random large enough integer is going to be hard to factor with high probability, but we might be unlucky.  There are also multi-party protocols for shared generation of RSA moduli (such as ), but I would like a non interactive technique.  Motivation: This was suggested by Poncho's answer to Where can I find every gnome? How to check if file exists on FTP before FtpWebRequest $e^{i\theta}=\cos\theta + i\sin \theta$  $e^{i\sin^{-1}x}=\cos(\sin^{-1}x)+i\sin(\sin^{-1}x)$  $i\sin^{-1}x=\ln|\sqrt{1-x^2} + ix|$  $\sin^{-1}x=-i\ln|\sqrt{1-x^2} + ix|$  Now from here I'm kind of lost, since it seems like this should be the definition, but when I look it up, the definition of inverse hyperbolic sine is:  $\sinh^{-1}x=\ln(\sqrt{1+x^2} + x)$  So although they're very similar, I guess I just don't know how to handle the logarithm and anything to the ith power or drop off the absolute value. MacBook is displaying the message "no hardware installed" when I click on Wi-Fi I have a MacBook Pro 2009 running MacOS El Capitan. Recently the Wi-Fi has stopped working.   When I click on the Wi-Fi icon it displays the message "No hardware installed", but Ethernet still works.   Is there any way of fixing this by using a Wi-Fi dongle or something of the sort, if so do I need a specific dongle and how do I install it? Center of a group ring? Let $R$ be a ring with unity and let $G$ be a group. Then what is the center of the group ring $R(G)$? I feel that the center $Z(R(G))$ is $R(Z(G))$. I assumed if $x=\sum_{i=1}^{n} r_i g_i$, then it should commute with every element of $R(G)$. In particular it should commute with $g=1 \cdot g \in R(G)$ Thus we get $$\big(\sum_{i=1}^{n} r_i g_i\big)g=g\big(\sum_{i=1}^{n} r_i g_i\big)$$ Thus I get $$g_i \cdot g=g_i \cdot g \text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ } \forall g \in G$$ Hence $x \in Z(R(G)) $. Is this correct? Why is "bicycle" pronounced differently from other obviously related words? How to fix "-5 No address associated with hostname error" while updating? Existence of elements of order $p^k$ in a finite group By Cauchy's theorem, if a prime number $p$ divides the order of a group $G$, then there is an element $g$ in $G$ whose order is $p$. In addition, if $|G|$ admits a prime decomposition with a factor $p^k$, then Sylow's theorem tells us that a subgroup of order $p^k$ must exist.   My question is the following. If $|G|$ admits a prime decomposition with a factor $p^k$, does this imply that an element of order $p^k$ must exist in $G$?   Update: As explained in Mindlack's answer (among others), the implication does not hold and simple counterexamples exist. In the comments, Mindlack discusses special cases where such an element exists.