Induction divisibility
Proving divisibility of expression using induction
MicroSD card is set to Read-only state. How can I write data on it? I have a MicroSD card reader in my notebook. When I insert a MicroSD memory card into it, I can't write any data on it - it's read-only. The same thing happens when I try to do it under root. And I can't change the permission policy for it. This problem happens for all microSD cards (I've tested 2 cards). I've encountered it on Ubuntu 12.04 LTS, now I'm on Ubuntu 12.10, the problem is still on it's place. When I try to insert such a "read-only" card in my mobile phone, everything's OK and I can write data on it. So, can anybody tell me, how can I write a data onto the card?  UPD: here's fdisk -l output:  Disk /dev/sdc1: 2013 MB, 2013135360 bytes 62 heads, 62 sectors/track, 1022 cylinders, total 3931905 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000   Device Boot      Start         End      Blocks   Id  System   The file system of the card is msdos. As to me it's weird.   UPD2: I've found a small "lock" switch on my card adapter, and it turns out, that when I insert it in my notebook, it switches on. Perhaps, I have to find some glue or something to get that switch stuck...  UPD3: There was no glue near me, so I've decided to buy another card-reader. Checking incoming call in iphone How can I sanitize user input with PHP? Is there a catchall function somewhere that works well for sanitizing user input for SQL injection and XSS attacks, while still allowing certain types of HTML tags? Proper way to exit iPhone application? UIRefreshControl without UITableViewController Reading Excel files from C# Is there a free or open source library to read Excel files (.xls) directly from a C# program?   It does not need to be too fancy, just to select a worksheet and read the data as strings. So far, I've been using Export to Unicode text function of Excel, and parsing the resulting (tab-delimited) file, but I'd like to eliminate the manual step. How to show the inequality for $\int_{0}^{\pi/4}\tan^n(x) dx$ I can't seem to figure out the inequality option, I substituted n=2 for the answer bit is there any elegant way of getting it? Is it possible in PHP to do something like this? How would you go about writing a function? Here is an example. The order is the most important thing.  $customer['address'] = '123 fake st'; $customer['name'] = 'Tim'; $customer['dob'] = '12/08/1986'; $customer['dontSortMe'] = 'this value doesnt need to be sorted';   And I'd like to do something like   $properOrderedArray = sortArrayByArray($customer, array('name', 'dob', 'address'));   Because at the end I use a foreach() and they're not in the right order (because I append the values to a string which needs to be in the correct order and I don't know in advance all of the array keys/values).  I've looked through PHP's internal array functions but it seems you can only sort alphabetically or numerically. What is a good complex analysis textbook, barring Ahlfors's? I'm out of college, and trying to self-learn complex analysis. I'm finding  text difficult. Any recommendations? I'm probably at an intermediate sophistication level for an undergrad. (Bonus points if the text has a section on the Riemann Zeta function and the Prime Number Theorem.) The meaning of various equality symbols New UI encourages askers to confirm or dispute duplicate votes , the banner shown to askers whose questions have attracted at least one duplicate close vote has a couple of new options:    If the author clicks the first button, they're shown a confirmation that clarifies the results of this action somewhat:    If they click "Ok", the question is instantly closed:    If, instead, they edit, they'll be offered this guidance:    ...and once an edit is submitted the choice will go away until another duplicate close-vote is cast.   In just the past day, 80 questions  network-wide have been closed in response to confirmation from the asker; edits by askers are up significantly as well.   We'll be monitoring the results to see if further adjustments are needed. A few open questions surrounding this change include:    Perhaps if the number of votes is below some threshold?   I'm posting this separately from  to allow room for discussion and . Why do prisms work (why is refraction frequency dependent)? It is well known that a  can "split light" by separating different frequencies of light:    Many sources state that the reason this happens is that the  is different for different frequencies.  This is known as .  My question is about why dispersion exists.  Is frequency dependence for refraction a property fundamental to all waves?  Is the effect the result of some sort of non-linearity in response by the refracting material to electromagnetic fields?  Are there (theoretically) any materials that have an essentially constant, non-unity index of refraction (at least for the visible spectrum)? I´m having some trouble with my udev rule. At the moment, I had my udev rule setup to execute a script whenever a Android phone is connected to any USB port on the computer. But I don´t want the script to be executed from every USB port. I just want that the script to be execute in example when the phone is connected to the 4th USB port and nothing should happen when it is connected to 1st, 2nd or 3rd USB port.  How can I achieve that and how can I determine the for example 4th USB Port?  I would highly appreciate your help.  My current udev rule:  KERNELS="1-2:1.1", ACTION=="add", ENV{DEVTYPE}=="usb_device", ATTRS{idVendor}!="1d6b", ATTRS{idVendor}!="203a", ATTRS{idVendor}=="****", ATTRS{idProduct}=="****", RUN+="/usr/local/bin/tmp.sh $attr{serial}" What is the distance a creature or player can travel if they have multiple types of movement speeds? How to pass argument to script which is input to bash References to a comment on a deleted answer can break Stack Exchange JS For the following URL, JavaScript breaks:  https://stackoverflow.com/questions/16356382/splitting-a-braces-grouped-string-in-python/16356421?noredirect=1#comment23433042_16356421   This is a link to a , the answer I can see as a 10K+ user (although users &lt;10k ).  With Chrome (26, Mac OS X) the console sez:  Uncaught TypeError: Cannot call method 'replace' of undefined   for line 83 of full.js.  Firefox (20, Mac still), the web console spits out:  [12:48:28.459] TypeError: c.attr(...) is undefined @ http://cdn.sstatic.net/js/full.js?v=c9131e40e3fb:83   Safari (6.0.4 on, you guessed it, Mac OS X) has this to complain about:  TypeError: 'undefined' is not an object (evaluating 'c.attr("id").replace')   for line 83 of full.js.  Because of this, the Answer text box on Stack Overflow is lacking all niceties such as an actual WMD editor.  If you remove the hash reference #comment23433042_16356421 from the end of the URL, things work again. Removing the ?noredirect=1 query parameter makes no difference. Don't replicators make the Ferengi rather pointless? Ferengis are all about acquisition and making a profit. But, in the age of replicators, where everything you want can be produced instantly, what would be the point of their lifestyle? How can I mass rename files? I've got a bunch of files named with a the pattern 99 - DescriptiveName.txt and I'd like to remove the number from the front so I just have DescriptiveName.txt.  How can I do this? Can I do it from the command line or is there a utility that can do this? The series $\sum_{n=2}^{\infty }\frac{1}{\log (n!)}$ I'm trying to find out whether this Series $\sum_{n=2}^{\infty } a_{n}$ converges or not when $$a_{n}=\frac{1}{\log (n!)}$$  I tried couple of methods, among them: d'Alembert $\frac{a_{n+1}}{a_{n}}$,   Cauchy condensation test $\sum_{n=2}^{\infty } 2^{n}a_{2^n}$, and they both didn't work for me.  Edit: I can't use stirling, and integral.  Thank you More than once I've accidentally run a number of commands and polluted my bash history. How do I close my terminal without saving my bash history? I'm using Fedora.