How should I connect four resistors to double the capacity with the same resistor?
Getting higher power output by using more resistors
Easiest way to read from and write to files This is a question to experienced people that might help us shed some light on the issue.   We noticed a very strange behavior on our site, in Google Analytics. Some dude from Finland, namely, from Kouvola city is hitting one of our pages - only one page on our site, 'bout a hundred times per day, all with an average bounce rate of 90%+...  This is causing our overall bounce rate to go up by 1 to 3% per day... which is very disturbing.. since we're trying to do our best in order to keep it as low as possible. And obviously having it jumped from ~24% to 27%, just because of that crazy dude is not making us happy at all... We tried implementing a geo-targeted script in order to catch this particular visitor and deliver him a juicy message, and it seemed like it helped in the beginning, it has stopped for a day or two, but now he's back...   The geo-targeted script was also logging all IP addresses for page requests originating from Finland in order to find out more details and (in order to block them on the server level, later).. but thing is, it was all mainly cable or DSL connections with various, but not constantly repeating IPs... we are all wondering what is he up to really ?   I think that this page should be kept updated with ideas on how to combat this and perhaps someone could also shed light on what it might be ? What is the reason for doing this "bounce-rate attack", as I call it?  There was a similar question asked on stackoverflow earlier, with no meaningful answer - here - How to increase difficulty in Dungeon World I've been GMing for a couple of sessions now and I'm still struggling at making encounters or situations more difficult. I will describe dangerous situations and encounters in fiction but the mechanics make it too easy for my players to succeed.  For instance no matter how big I describe the Troll, if the fighter of the party charges him and swing his sword, roll+2 for Hack and slash, he'll easily hit the troll. Almost 40% chance to hit without consequences. What is the difference between a field and a property? Ensure a burned DVD will work any dvd player? How do I backup a LVM partition to an image for recovery purposes?  I am trying to run dd on /dev/sda2, but it crashes after ca 8 hours, at around 380G   sudo lvmdiskscan   /dev/centos/swap [       3.89 GiB]    /dev/sda1        [     500.00 MiB]    /dev/centos/root [      50.00 GiB]    /dev/sda2        [     465.27 GiB] LVM physical volume   /dev/centos/home [     411.38 GiB]    /dev/sdb1        [     931.51 GiB]    3 disks   2 partitions   0 LVM physical volume whole disks   1 LVM physical volume   Anyway, could running from a stick make any difference? How can I write a program that can detect by itself that it has been changed? I need to write a small program that can detect that it has been changed. Please give me a suggestion!  Thank you. Heartbleed: What is it and what are options to mitigate it? How do I ensure that figures appear in the section they're associated with? Often floats may land quite a bit later in the document than the point they are created, sometimes after a section break.  Is there a way to force a new section to start on a new page, after any unplaced floats? How many 6-letter permutations can be formed using only the letters of the word, MISSISSIPPI? I understand the trivial case where there are no repeating letters in the word (for arranging smaller words) but I stumble when this isn't satisfied. I'm wondering if there's a simpler way to computing all the possible permutations, as an alternative to manually calculating all the possible 6-letter combinations and summing the corresponding permutations of each. In addition, is there a method to generalize the result based on any P number of letters in a set with repeating letters, to calculate the number of n-letter permutations?  Sorry if this question (or similar) has been asked before, but if it has, please link me to the relevant page. I also apologize if the explanation is unclear, or if I've incorrectly used any terminology (I'm only a high-school student.) If so, please comment. :-) Difference between a space and a "wave" symbol (tilde/"~")? My linear voltage regulator is overheating very fast I'm using a 5 V / 2 A voltage regulator () without a heatsink. I'm testing the circuit with a microcontroller (PIC18FXXXX), a few LEDs and a 1 mA piezzo buzzer. The input voltage is aprox. 24 VDC. After running for a minute, the voltage regulator starts to overheat, meaning it burns my finger if I keep it there for more than a second. Within a few minutes it starts to smell like it's burnt. Is this a normal behavior for this regulator? What could cause it to heat that much?    Other components used in this circuit:  L1:   R2:   F1: This is an exercise from Chapter 3 of Golan's linear algebra book.  Problem: Show $\mathbb{Z}$ is not a vector space over a field.  Solution attempt:  Suppose there is a such a field and proceed by contradiction. I will write multiplication $FV$, where $F$ is in the field and $V$ is an element of $\mathbb{Z}$.   First we rule out the case where the field has characteristic 2. We would have   $$0=(1_F+1_F)1=1_F1+1_F1=2$$  a contradiction.  Now, consider the case where the field does not have characteristic 2. Then there is an element $2^{-1}_F$ in the field, and   $1=2_F(2^{-1}_F1)=2^{-1}_F1+2^{-1}_F1$  Now $2^{-1}_F1\in\mathbb{Z}$ as it is an element of the vector space, but there is no element $a\in\mathbb{Z}$ with $2a=1$, so we have a contradiction.  Is this correct? Before:  After:   The pros:  Speeds up the tag synonym voting process. Easier to locate (as opposed to navigating to each individual tag wiki page). Encourages users to vote on more than one at a time.  The cons:  Serial up/downvoting. But this really isn't even an issue because, (1) only experienced users can vote on tag synonyms, and (2) more than one vote is required to approve a tag synonym, so the occasional serial up/downvoter won't significantly impact the overall process. Expanding electromagnetic field Lagrangian in terms of gauge field I am taking a course in Differential Topology right now, but I know of another Subject called "Riemannian Geometry" which studies Riemannian Manifolds. The definition of a real smooth manifold and a Riemannian Manifold are very similar except for the detail that makes them Riemannian (having a inner product on the tangent space of every element which varies smoothly with respect to this element of the R. Manifold).  So my question is: is there any example of a Smooth Manifold that is NOT a Riemannian Manifold?  Thanks. Which transformations are canonical? Which transformations are ? Regular Expression to match valid dates I'm trying to write a regular expression that validates a date.  The regex needs to match the following   M/D/YYYY MM/DD/YYYY Single digit months can start with a leading zero (eg: 03/12/2008) Single digit days can start with a leading zero (eg: 3/02/2008) CANNOT include February 30 or February 31 (eg: 2/31/2008)   So far I have   ^(([1-9]|1[012])[-/.]([1-9]|[12][0-9]|3[01])[-/.](19|20)\d\d)|((1[012]|0[1-9])(3[01]|2\d|1\d|0[1-9])(19|20)\d\d)|((1[012]|0[1-9])[-/.](3[01]|2\d|1\d|0[1-9])[-/.](19|20)\d\d)$   This matches properly EXCEPT it still includes 2/30/2008 &amp; 2/31/2008.  Does anyone have a better suggestion?  Edit: I found  on RegExLib  ^((((0[13578])|([13578])|(1[02]))[\/](([1-9])|([0-2][0-9])|(3[01])))|(((0[469])|([469])|(11))[\/](([1-9])|([0-2][0-9])|(30)))|((2|02)[\/](([1-9])|([0-2][0-9]))))[\/]\d{4}$|^\d{4}$   It matches all valid months that follow the MM/DD/YYYY format.  Thanks everyone for the help. How do I display a decimal value to 2 decimal places? How to adapt classicthesis layout to B5paper and Linux Libertine Question says it all: I am using classicthesis with XeTeX to typeset my PhD thesis. I want to use B5 paper size (176 × 250 mm) and the beautiful Linux Libertine font. I'm wondering how to    calculate the optimal page margins actually apply these settings to the document   Any help is greatly appreciated =)  EDIT: I should add that I need to generate two different PDF files from this:   a version with papersize A4 (210 × 297 mm), where the B5 layout is (approximately) centered, and crop marks are shown, to pass on to the printing company a version with papersize B5 for online distribution, having the same layout as the printed one.   I tried fiddling with using  and \areaset command, but to no avail.