When I try to download a free app it keeps sending me to the settings info about my card number. Then it says that there was a billing problem with a previous purchase. And to update my payment methods . I no longer have a credit card so how do I download free apps???
I just recently got an iPod Touch and wanted to download some free apps. The App Store wanted me to get an Apple ID, no problem. But now it's telling me to input a credit card. I don't have one, and anyway shouldn't need one to download free apps.   I did some searching here and on Google and found out that there should be a "None" option when selecting credit cards, but it was not there. I then read that it's disabled in some countried, so I tried telling iTunes that I'm in the US (I'm in Argentina), but still no "None" option. Later, I read that apparently this feature was disabled in iTunes 10, so I installed iTunes 9, but I still don't get the option.  How can I get the No Credit Card option to appear when downloading an app for the first time? It doesn't make sense that you should need a credit card for free stuff.  EDIT: To clarify, I already made an account in Apple's website, I'm looking for a way to be able to select "None" when buying an app through iTunes.
Multivariable Delta Epsilon Proof $\lim_{(x,y)\to(0,0)}\frac{x^3y^2}{x^4+y^4}$ --- looking for a hint I have the limit $$\lim_{(x,y)\to(0,0)}\frac{x^3y^2}{x^4+y^4},$$ and would like to show with an $\epsilon-\delta$ proof that it is zero. I know with a situation like $$\left|\frac{x^4y}{x^4+y^4}\right|\leq y$$  or something similar, but I can't find a way to do the same thing here, as no single term in the numerator is of sufficient degree, although I think I could get this with a small hint. How to combine measurement error with statistic error Why is the top bar not changed on Stack Exchange, Area 51 and Ask Ubuntu? I deleted a folder in Ubuntu, how can I recover it? The folder is massive (390GB) and contains many different files. The file system is ext4  I was about to copy this file to another hard drive using gksudo nautilus so I didnt have do a massive chmod operation on the destination hard drive, but then I accidentally hit move to trash, which in gksudo nautilus means permanent deletion. I checked the trash but it's not even an operation...  I have seen tools like testdisk and other recovery tools but none that can recover and whole folder because its made up of different files.   I don't think that this would work but if I deleted the partition could I just recover the whole partition at once?  Or would this be wrong because i have already deleted the partition's content? This is my first job in Linux IT.  I don't have a backup... I was trying to make one because the old backup drive died :( In bash, calling foo would display any output from that command on the stdout.  Calling foo &gt; output would redirect any output from that command to the file specified (in this case 'output').  Is there a way to redirect output to a file and have it display on stdout? Why doesn't my screen lock in XFCE? SQLiteException while inserting values in the database in Android Idempotent of closure and other properties How long do black olives last once opened? I opened a can of sliced black olives for my pizza and only used half. I put the leftovers into a sealed container with the liquid and put it in the fridge. Under those conditions how long will the olives last? Is there a better way to store leftover olives? extended stars-and-bars problem(where the upper limit of the variable is bounded) The problem of counting the solutions $(a_1,a_2,\ldots,a_n)$ with integer $a_i\geq0$ for $i\in\{1,2,\ldots,n\}$ such that $$a_1+a_2+a_3+....a_n=N$$ can be solved with a stars-and-bars argument. What is the solution if one adds the constraint that $a_i\leq r_i$ for certain integers $r_1,\ldots,r_n$?  e.g. for $n=3$, $N=6$ and $(r_1,r_2,r_3)=(3,3,2)$, the tuple $(a_1,a_2,a_3)=(2,3,1)$ is a solution, but $(2,1,3)$ is not a solution because $a_3=3&gt;2=r_3$. Difference between $ and # in Linux environment What test can I use to compare slopes from two or more regression models? I would like to test the difference in response of two variables to one predictor. Here is a minimal reproducible example.   library(nlme)  ## gls is used in the application; lm would suffice for this example m.set &lt;- gls(Sepal.Length ~ Petal.Width, data = iris,                 subset = Species == "setosa") m.vir &lt;- gls(Sepal.Length ~ Petal.Width, data = iris,                 subset = Species == "virginica") m.ver &lt;- gls(Sepal.Length ~ Petal.Width, data = iris,                 subset = Species == "versicolor")   I can see that the slope coefficients are different:  m.set$coefficients (Intercept) Petal.Width    4.7771775   0.9301727 m.vir$coefficients (Intercept) Petal.Width    5.2694172   0.6508306  m.ver$coefficients (Intercept) Petal.Width     4.044640    1.426365    I have three questions:   How can I test the difference between slopes? How can I test the difference between residual variances? What is a simple, effective way to present these comparisons?    A related question, , suggests re-running the model with a dummy variable to differentiate the slopes, are there options that would allow the use of independent data sets? Okay, so I understand what calculus, linear algebra, combinatorics and even topology try to answer (update: this is not the case in hindsight), but why invent category theory? In Wikipedia it says it is to formalize. As far as I can tell, it sort of generalizes a bunch of fields in mathematics, like in topology, graphs and groups we have isomorphisms and automorphisms and homomorphisms, it seems to me like it just finds a bunch of results that are true to these functions in a bunch of disciplines. But why would generalizing that be of use? I mean, wouldn't it be easier to prove them specifically in each of the important disciplines? Proving a trig identity: $\frac{\sin(A + B)}{\sin(A - B)}=\frac{\tan A + \tan B}{\tan A - \tan B}$ How should one maintain and update a MiKTeX installation? I'm playing around with fdisk and I tried to create a partition on an empty USB drive. Here's how that went: Command (m for help): n Partition number (1-128, default 1): 1 First sector (34-61187102, default 2048): 2048 Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-61187102, default 61187102): +30000000           Created a new partition 1 of type 'Linux filesystem' and of size 14,3 GiB.  so just one partition with 30 million sectors. However, when I check how many sectors it contains I get:  I'm checking with a different program and I see again that additional sector:  Sorry for the pettiness :) I'm learning. create a .deb Package from scripts or binaries I searched for a simple way to create .deb Packages for things which have no source code to compile (configs, shellscripts, proprietary software). This was quite a problem because most of the package tutorials are assuming you have a source tarball you want to compile. Then I've found  short tutorial (german).  Afterwards, I created a small script to create a simple repository. Like this:  rm /export/my-repository/repository/* cd /home/tdeutsch/deb-pkg for i in $(ls | grep my); do dpkg -b ./$i /export/my-repository/repository/$i.deb; done cd /export/avanon-repository/repository gpg --armor --export "My Package Signing Key" &gt; PublicKey apt-ftparchive packages ./ | gzip &gt; Packages.gz apt-ftparchive packages ./ &gt; Packages apt-ftparchive release ./ &gt; /tmp/Release.tmp; mv /tmp/Release.tmp Release gpg --output Release.gpg -ba Release   I added the key to the apt keyring and included the source like this:  deb http://my.default.com/my-repository/ ./   It looks like the repo itself is working well (I ran into some problems, to fix them I needed to add the Packages twice and make the temp-file workaround for the Release file). I also put some downloaded .deb into the repo, it looks like they are also working without problems. But my self created packages didn't... Wenn i do sudo apt-get update, they are causing errors like this:  E: Problem parsing dependency Depends E: Error occurred while processing my-printerconf (NewVersion2) E: Problem with MergeList /var/lib/apt/lists/my.default.com_my-repository_._Packages E: The package lists or status file could not be parsed or opened.   Has anyone an idea what I did wrong?  UPDATE 2012-03-06: Just a a hint for another person who is searching for a easy way to create DEBs: Take a look at . I (think) that I've configured a static IP address in /etc/network/interfaces:  # The primary network interface  auto eth0  iface eth0 inet static     address 10.1.1.2     netmask 255.255.255.0     network 10.1.1.0     broadcast 10.1.1.255     gateway 10.1.1.1   And I change the file /etc/resolv.conf to include the desired nameservers.   Then I restart networking sudo /etc/init.d/networking restart  But after some hours resolv.conf always reverts back to the DHCP nameserver.   I should also say that this is Ubuntu Server with only l0 and eth0 interfaces. Would time freeze if you could travel at the speed of light? Which "mean" to use and when? So we have arithmetic mean (AM), geometric mean (GM) and harmonic mean (HM). Their mathematical formulation is also well known along with their associated stereotypical examples (e.g., Harmonic mean and it's application to 'speed' related problems).  However, a question that has always intrigued me is "how do I decide which mean is the most appropriate to use in a given context?" There must be at least some rule of thumb to help understand the applicability and yet the most common answer I've come across is: "It depends" (but on what?).  This may seem to be a rather trivial question but even high-school texts failed to explain this -- they only provide mathematical definitions!  I prefer an English explanation over a mathematical one -- simple test would be "would your mom/child understand it?"