Can I download apps without having an apple id? Is it possible to download apps on iPhone 4 without creating an Apple ID ?
How can I download free apps without registering an Apple ID? "This Apple ID has not been yet been used before in the iTunes Store. Tap review to sign in, then review your account information."   I keep getting this message when I try to install free apps from App Store. I don't want to give my account info until I actually purchase something.   Can I not download free apps until I provide my account information? My email verification is complete. I'm using an iPhone 3GS logged in to my iTunes account.
How do you transpose tensors? We transpose a matrix $A$ by replacing $A_{ij}$ with $A_{ji}$, for all $i$ and $j$.  However, in case $A$ has more than two dimensions (that is, it is a tensor), I don't know how to apply the transpose operation.   If A has dimensions $3\times 3 \times 8$, then what will replace $A_{ijk}$?  If $A$ has shape $3\times 3\times 8\times 8$, then what will replace $A_{ijkl}$? Let $M$ be the space of all $m\times n$ matrices. And $C=\{X\in M|rank(X)\leq k\}$ where $k\leq \min\{m,n\}$. How to proof that C is a closed subset of M? I need to calculate the Cramer Rao lower bound of variance for the parameter $\theta$ of the distribution $$f(x)=\frac{1}{\pi(1+(x-\theta)^2)}$$   How do I proceed I have calculated $$4 E\frac{(X-\theta)^2}{1+X^2+\theta^2-2X\theta}$$  Can somebody help Is there any software to sync files-folders and software between two PCs? For example if I install program 'A' to my desktop I want to be installed to my laptop as well if I have synchronized these two. I want the same with my files and folders. If I change something to my desktop I want the changes to effect my laptop too(I exclude Ubuntu One as a solution).  Thanks for your time and patience! I have a mathematical problem with the following formula. The goal is to transform this equation to have a seperated real and imaginary part. I have already done this with several other equasions, but for this particualar one I don't know where to start.  I dont expect you to do the complete work of transforming for me, it would already be very nice if you could give me a hind on how you would start.  Thank you in advance!  C||RLC      This is my current progress:    My question is:  How can I get rid of the imaginary part jωC2*R?  When the denominator is completely real I can just split up the formula and have an imaginary and a real part. Estimate of analytic function in a unit disk Convert LaTeX to HTML Is there a converter that will convert LaTeX to HTML? I have tried several services but the LaTeX diagrams and some of the maths came out weird.  I actually converted the Latex to PDF without a problem. Then I used  to convert from PDF to HTML. The square root signs did not appear properly and some of the Cartesian coordinate plane diagrams had nothing on them except the grid.   \documentclass[12pt,a4paper]{report} \usepackage{amssymb} \usepackage{amsthm} \usepackage{amsmath} \usepackage{pstricks,pst-plot} \usepackage{pst-eucl} \addtolength{\hoffset}{0.2cm} \addtolength{\textwidth}{1.1cm} \addtolength{\textheight}{1.0cm} \addtolength{\voffset}{-0.7cm} \linespread{1.3} \begin{document}  If $x$ is non-positive then $x \leq -\sqrt{\frac{1}{2}}$     $\hspace{30 mm} $     (6)\\  (4) and (6) tell us that\\  (4)  $-1 \leq x \leq 0$  \\  (6)  If $x$ is non-positive then $x \leq -\sqrt{\frac{1}{2}}$\\  Therefore $-1 \leq x \leq -\sqrt{\frac{1}{2}}$\\  \vspace{50 mm}  \begin{align*} \psgrid[unit=2cm](0,0)(-2,-2)(2,2) \pnode(-1.8,.87){b}\uput[50](b){b} \pnode(-1.8,1.8){a}\uput[50](a){a} \psset{linecolor=green} \psline[linewidth=1pt](-1.8, 0)(-1.8,4) \psset{linecolor=green} \psline[linewidth=1pt](-1.8, 0)(-1.8,-4) \psset{linecolor=blue} \psellipticarc(0,0)(2,2){0}{180} \psset{linecolor=red} \psline[linewidth=1pt,linestyle=dashed,dash=2pt](-2,2)(-1.41,1.41) \psset{linecolor=red} \psline[linewidth=1pt](-1.41,1.41) \psset{linecolor=red} \psline[linewidth=1pt]{-&gt;}(4,-4) \psset{linecolor=red} \psline[linewidth=1pt]{-&gt;}(-2,2)(-4,4) \end{align*}  \end{document}   PDF output:    PDF->HTML output: Why is $SO(3)\times SO(3)$ isomorphic to $SO(4)$? Remove sudo privileges from a user (without deleting the user) Don't count non-printing characters, HTML comments or other content not displayed toward minimum character requirements A follow-up to , and an extension of .   shows that it is possible to circumvent minimum character requirements using null bytes.  Can we exclude such non-printing characters as ASCII NULL and other control characters from counting toward minimum character requirements?  Edit: Users have demonstrated that , unmatched or invalid HTML tags, and other content that is not displayed after Markdown parsing can be used to bypass such requirements as well.  Can we cover this case as well, except for links? I'm currently working my way through Harvard's online abstract algebra lectures (if you're interested, you can find them ).  The lectures come complete with notes and homework problems.  Of course, since I don't actually go to Harvard, I can't hand in the homework assignments to find out if I'm doing them correctly.  So I've decided to try to crowd source the grading of my solutions.  I'll post individual questions as I finish them and wait for comments.  I would like to get critiques of not just my reasoning but the style of my write ups as well.  Also, any alternative approaches to the problem would be welcome.  I've looked for forums dedicated to these kinds of OCW courses but have not been able to find any.  This surprises me.  It seems like, with the advent of these free online educational resources, an online meeting place for those who take advantage of them would be a natural offshoot.  So this might be a bit of an experiment.  Unless I'm the 873rd person to post something like this here.  If that's the case, sorry for being so long winded.  Anyway, on with the question.  This one is assigned in the 4th lecture.     Let $V$ denote the Klein 4-group.  Show that $\operatorname{Aut}(V)$ is isomorphic to $S_3$.   (I've moved my solution below to keep this question from showing up in the unanswered list.)  Thanks... I am being flown out by a company for an on-site visit. Will I earn miles for this trip, or will the company? How to prove there are no more positive integers that are products of 2 and 3 consecutive numbers? $6$ and $210$ share the property that both are the products of both two and three consecutive numbers. $6$ is $2\times3$ and $1\times2\times3$ and $210$ is $14\times15$ and $5\times6\times7$. It was easy enough to write a program to search for more numbers with this property, I found that there were no more up to at least $1{,}000{,}000{,}000{,}000$ ($1$ Trillion). But it is beyond me to prove that there are either no more numbers like this or to find the next one. Any ideas? After my lie down, I posted  on SO. As I suspected would happen, it got moved to programmers. Unfortunately, the kind of people I'm interested in getting answers from (litb,skeet et al - the top SO programmers in their respective disciplines) don't frequent Programmers much. So my question is, where to ask somewhat non-specific questions of high-powered users? How to line up the pieces at the coast near the shipwreck? In The Witness, I was walking along the coast, and I came upon this:    Now, since I've learned      that mazes can be embedded in the environment,   I see the puzzle here, but I just can't get the pieces to line up well enough.  Standing on the couch and walking all around it doesn't seem to get me a       functional maze.   Where do I need to stand to activate the puzzle successfully? I am working on a BLDC sensorless motor. I need to detect BEMF Zero-cross event. My Motor is working on 24 Volt power.  Now I need to detect the back E.M.F. As refered in .  My MCU is working on 5V. And ADC range is 0 to 5V. I need to convert the BEMF feedback signal to ADC channed in this.  As we know voltage divider rule says:   In Figure I :-- Now signal (U) which I need to feed is applied at the middle of the two resistors R1 &amp; R7. So what is the value of voltage VU ?   In Figure II :-- Sum of U,V,W  is applied at the middle of the two resistors R11 &amp; R15. So what is the value of voltage VN ?  Also, what are the roles of capacitors C1 &amp; C4?  Please can someone explain the MATH behind this ? Partial or entire Image Blurring in TikZ?  I have seen some examples of drop shadow blurring in the pgf-blur package version 1.01 by Martin Giese but this isn’t what I mean.  Is it somehow possible to do partial or entire Image Blurring in TikZ, just like what one may do in Adobe Photoshop? In Windows you have a C-drive. Everything labeled beyond that is with the following letter.   So your second drive is D, your DVD is E and if you put in a USB stick it becomes F and the following drive G. And so on and so forth.  But then, what and where are A and B-drives? mean value theorem question I was trying to solve the following:  Given: $0 &lt; a &lt; b$ and $n&gt;1$, prove: $$na^{n-1}(b-a) &lt; b^n-a^n &lt; nb^{n-1}(b-a)$$  I managed to get this far using the mean value theorem: $$a^n(b-a)&lt;b^n -a^n&lt;b^n (b-a)$$ Any idea how to continue? It is possible to make ls -l output the size field with digits grouped by thousands? If so, how?  For instance:  $ ls -l -rw-rw---- 1 dahl dahl 43,210,052 2012-01-01 21:52 test.py   (Note the commas in the size).  Maybe by modifying the LC_NUMERIC setting inside the locale I'm using (en_US.utf8)?  I'm on Kubuntu 12.04 LTS.