Baking more than 1 cut of meat at same time?
Oven temperature for multiple ducks?
Derivative of the product of operators and Derivative of exponential I'm asked to show that  $$\frac{d(\hat{A}\hat{B})}{d\lambda} ~=~ \frac{d\hat{A}}{d\lambda}\hat{B} + \hat{A}\frac{d\hat{b}}{d\lambda}$$ With $\lambda$ a continuous parameter. Should I use the definition $$\frac{d\hat{A}}{d\lambda} ~=~ \lim_{\epsilon \to 0} \frac{\hat{A}(\lambda + \epsilon) - \hat{A}(\lambda)}{\epsilon}$$ applied to $\hat{A}\hat{B}$ like $$\frac{d(\hat{A}\hat{B})}{d\lambda} ~=~ \lim_{\epsilon \to 0} \frac{\hat{A}(\lambda + \epsilon)\hat{B}(\lambda + \epsilon) - \hat{A}(\lambda)\hat{B}(\lambda)}{\epsilon}$$ and do some algebra to get the RHS of the first equation, or I'm missing something? Another interesting derivative to pay attention to is: $$\frac{d}{d\lambda}\exp(\hat{A}(\lambda) )~?$$ All I want to do is to check whether an element exists in the vector or not, so I can deal with each case.  if ( item_present )    do_this(); else    do_that(); To seek the maximum value of $S=x_1x_2+x_2x_3+\cdots+x_nx_1$ on this domain:  $x_1+x_2+\cdots+x_n=0$ and  $x_1^2+x_2^2+\cdots+x_n^2=1$.  I have made some trivial observations:  1) $S\in[-1,1)$ by the rearrangement inequality.  2) We can make $S$ arbitrarily close to $1$ by increasing $n$.  3) An equivalent problem is to minimise $(x_1-x_2)^2+\cdots+(x_n-x_1)^2$.  But does the maximum have a meaningful closed form  for each $n$? Why aren't hash values for "nothing" (empty) defined as all zeros? Any decent hash algorithm will produce basically "random like" values for any given input including the empty input.  For example MD5 produces d41d8cd98f00b204e9800998ecf8427e on an empty input.  I wonder, however, why the MD5 algorithm wasn't defined to have a final step where the output is XORed with d41d8cd98f00b204e9800998ecf8427e. This should not affect the cryptographic strength of the hash algorithm, and it would have the convenient property that a hash of all zeros represented a zero input.  Would it simply just because adding that step would slow the hash down a bit? After what speed air friction starts to heat up an object? I understand that air friction cools off an object at low speeds. For example, if you blow on a spoon of hot soup, it cools off. Or if you swing a hot frying pan in the air, it cools off faster.  But at higher speeds, the situation changes in the opposite. For example, consider a meteor falling on Earth. It is so fast that it heats up to such a high temperature that it burns into ashes.  What is the critical speed in which an object starts to heat up?  For example, consider a spherical object with radius of 1 meter. Let its density be 1 g/cm3 if needed. And let the air pressure be 1 atm. Assume that the temperature of the object is 400 K and the temperature of the air is 300 K. Also assume that the specific heat constant of the material is 1 cal/(gr.K). What is the critical speed for this object after which its temperature starts to rise above 500 K? Lebesgue integration: $f = g$ a.e. $ \Rightarrow \int_\Omega f = \int_\Omega g$ Let $f,g : \Omega \subseteq \mathbb R^n \rightarrow [0,+\infty]$ be measurable functions with $f(x) = g(x)$ a.e. . Then I have to show that $\int_\Omega  f = \int_\Omega g$.  I may not assume that $\int_\Omega (f+g) = \int_\Omega f + \int_\Omega g$.   This task is from Tao Proposition 19.2.6. How to resize partitions? Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers.  Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions).  Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space.  How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions? Can a mangaka continue another mangaka's manga? There are plenty of manga that never had an ending for many reasons. For example, High School of the Dead's mangaka, Daisuke Satou, . Some mangaka also cannot continue their work because of health problems, as well as other reasons. Say the original mangaka either prepared or did not prepare an ending himself/herself, can another mangaka continue their work? Has this ever happened before? What's the C++ way of parsing a string (given as char *) into an int? Robust and clear error handling is a plus (instead of ). Where do I suggest new Stack Exchange sites? Is there an appropriate place to suggest new Stack Exchange based sites, perhaps a place for them to be voted upon?  I wish there was a Stack Exchange site for Aviation (both real-life and simulated). How to distinguish gift from payment for the service? If somebody gives me reasonable advise or share important to me information.   Being attentive I would like to make a little gift or give some little (&lt;100$) amount of money (cash/wire/online) for that   How it would be classified by IRS?   Which obligations originate with this matter for me and my party?  How to do this in a most comfortable way to my party? Early 80s anthology book about human kind being feared by other races in space I always thought the book was Manifest Destiny but its not. The story that sticks in my head was a human in a cage over a pit? Aliens walk in and discuss how dangerous humans were. He eventually escapes. Man I miss this book. wish I wouldve written down every book I ever read. Ugh Does going outside the range of the spell or breaking line of sight between the caster and target break concentration or otherwise affect control over the spell?  For example, a Heat Metal spell has a range of 60 ft. If I cast the Heat Metal spell on a an armored foe, and that foe runs outside the range of the spell (60 ft), or around the corner, does that break concentration and end the spell? Heat Metal also allows you to use a bonus action to cause the 2d8 of damage — would exercising that option be prevented by being out of range or line of sight? How does the tmp folder work? It stores lots of junk files and takes space My tmp folder is set to /sites/default/files/tmp/ and I checked what's inside and for example there is folder inside called /update-cache-b2903cc4/ it keeps all modules in .zip that I installed via 'Install from a URL'. So why are those modules .zip files are kept there in tmp folder, isn't it a waste of storage? I don't really like it when the site is full of unnecessary files.  Am I supposed to delete these by myself all the time? C++ namespace and include Why do we need both using namespace and include directives in C++ programs?  For example,   #include &lt;iostream&gt;  using namespace std;  int main() {  cout &lt;&lt; "Hello world"; }   Why is it not enough to just have #include &lt;iostream&gt; or just have using namespace std and get rid of the other?  (I am thinking of an analogy with Java, where import java.net.* will import everything from java.net, you don't need to do anything else.) why normalize and the definition of directional derivative Local colormaps in global coordinate system I am trying to get a surface graph with two colormaps.  Instead of using the full Z range i want to give the first surface its own colormap  and the second surface should receive its own colormap too (it may be even the same)... however the current version takes the full range of Z-Data and calculates the colormap. Is there any way?  \begin{tikzpicture}     \begin{axis}[grid = major, colormap={bw}{gray(0cm)=(0); gray(1cm)=(1)}, view={-30}{15}]   \addplot3[surf]    table     {DATA1.dat};   \addplot3[surf]    table     {DATA2.dat};  \end{axis} \end{tikzpicture}   Right now it looks like that:   I want each of the surface to be scaled individually... just to see more clearly how the amplitude changes :)  Any ideas?  Thanks, Alex I'm trying to determine which battery to use for my application. I'll be using a class 1 or class 2 Bluetooth (not low energy) module, which requires about ~50/60mA of RX/TX current. In addition, there is a microcontroller and some low power analog IC's. I require a continuous stream of data from the device for 1-10 minutes.  Are coin cells completely out of the question? I'm talking about CR2450 Lithium-ions. I don't really mind if they don't last long, but will they work? Because in my application, size is key, and battery life is a trade off that I'm willing to make. I was just awarded +100 reputation on all of my Stack Exchange accounts.  What is this bonus for? It simply says "Association Bonus" on my reputation overview.  Also:   What privileges does the association bonus grant users? Can I lose the association bonus? Does it make my reputation 101 everywhere? Can I earn the association bonus on sites I haven't joined yet? Does it matter which site I earn the 200 reputation on? Will I get an association bonus every time my reputation on a site crosses 200 points? Does the association bonus allow me to answer protected questions? Does the association bonus count towards the reputation cap? Can I get the association bonus if I only have a profile on one site? What else is there to know about the association bonus? Can we divide two vector quantities? For eg., Pressure( a scalar) equals force (a vector) divided by area (a vector).