Why does QGIS save EPSG:4326 as long, lat?
EPSG:4326 being saved as CRS:84
Quaternions, Rotations and Real numbers I haven't really formally studied Algebra at anywhere near this level, but I was told about the existence of Quaternions a few years ago and I find them really cool. I also like how pure quaternions are analogous to cross products in $R^3$, and that it gives me a way of doing it algebraically rather than relying on hand rules.  Over the course of using them it's my understanding that multiplying an element by another, both imaginary numbers, rotates it in some manner so as to be orthogonal to both, similar to rotations of $\frac{\pi}{2}$ in the space with one real and one imaginary axis when multiplied by $i$, which is why it's useful for cross products as it will rotate it to be orthogonal to a plane spanned by linear combinations of those two vectors [afaik].   What I can't intuit though is why for any pure quaternion multiplication, there's a negative real part [the scalar product] if it's meant to correspond to a rotation within $R^3$ and the space of pure Quaternions is Isomorphic to $R^3$. Similarly I don't understand why $i^2 = j^2 = k^2 = $ A negative real. I remember reading a book in high school where a group of people travel to an alien planet where they discover an alien civilization separated into 2 castes. they are then made slaves to the taller class of aliens and one man has the flesh removed from his hands to make his fingers appear longer. The number of (non-equal) forests on the vertex set V = {1, 2, ...,n} that contains exactly 2 connected components is given by The number of (non-equal) forests on the vertex set V = {1, 2, ...,n} that contains exactly 2 connected components is given by $\sum_{k=1}^{n-1} {n-1 \choose k-1} k^{k-2} (n-k)^{n-k-2}$.  I am unsure how to approach this question. Could someone guide me through the proof? If G is a spanning tree and it is disconnected then I know it is a spanning forest. Also, I know by Cayley's thm that there are $n^{n-2}$ nonequal tree on a vertex set V = {1, 2, ...,n} which is where i'm assuming the $k^{k-2}$ comes from but I do not understand where the rest of it is coming from. How to use AT commands in Android by 'root' the phone We have various Android devices from Spike, Samsung, Micromax, etc. How can we issue AT commands from Android to the modem? We searched in Google Play but did not find any app related to this.   suggests:     [F]irst you have to root the phone...`    How can we do this? Looking for a YA book about a boy that learns to use powers from an adept in a weird house that appears abandoned from the outside I am looking for a YA book about a boy who learns to use powers from a mind-adept, in a seemingly abandoned house. The adept helps him open his mind by using a cube. One of his powers, I believe, is to go into dreams of people that  he knows. He helps his young female neighbor friend by doing this, opening a door in her mind. He tries to open the mind-door of a local older bully, but finds out the young man can't be helped because he has been abused mentally and physically. I don't believe the book I read is past 1995. It might have the word "adept" in it. When should we use "can", "could", "will", "would"? Most people say I wish I could, I wish you would.    Can we use I wish I can, I wish you will?    I'd like to know what the main differences between the usage of can/will and could/would are when wishing.  Is it related to the subjunctive? Because one says “I wish I were”, not “I wish I am”, so are would and could the subjunctive forms of can and will?  Or is it something else entirely? Consecutive spoiler blocks (>!) are shown as blockquotes The markdown &gt;! a  &gt;! b  &gt;! c  Will be shown as a blockquote with ! in front of it:   a    b    c  Instead of a spoiler for 3 paragraphs (or 3 spoiler blocks, whatever). This girl that I'm friends with and have actually seen in person before, keeps posting [on social media] that she "loves when the transfer goes through" and gets $2000-$6000 for free quite often. She said you can make up to $6500 a day. She is not very smart and barely spells correctly. She keeps saying that all she is doing is "transfers" and that's it. So many of my friends are feeding into this crap. So I asked her what it is. She basically said "it's legit" and asked me for my bank username and password so she could see how much money to deposit into my account. I said no way and left it at that. She also said she is not stealing or doing anything illegal. She is getting her friends free money and I think they're naive. What is she actually doing? Is it illegal? I am sure she is incapable of doing crazy money wiring to different countries.   Thank you everyone for answering my question. I am not stupid, I did not give her my information. I knew she was up to something illegal, so thank you for giving me some input on what exactly she is doing. I submitted an anonymous tip to my local sheriff's department. I'm hoping they see it and pursue it, or forward it to the right authorities I.e the FBI or something. Does Windows still rely on MS-DOS? I am just about to start an OS course and as an Apple user I am not very familiar with the underlying details of Windows OS. I was wondering, is MS DOS still used with Windows running on top or is ONLY Windows used now as the OS? I was a little confused because I read somewhere that MS-DOS is used for booting but Windows has all other OS capabilities built into it and thus is used for all other OS operations... Let $f(z)$ be a holomorphic function on a disk of radius $&gt;1$ about the origin, and suppose that $|f(z)|\leq 1$ for $z$ with $|z|=1$ and $\text{Re}(z)&gt;0$ and $|f(z)|\leq 2$ for $z$ with $|z|=1$ and $\text{Re}(z)\leq 0$.  How does one show the bound $|f(0)|\leq \sqrt{2}$? $S$ be a collection of subsets of $\{1,...,100\}$ ; any two sets in $S$ has non-empty intersection , what is the maximum possible value of $|S|$? What solutions does the equation $4x\equiv2\mod10$ have? (Hint, it will have more that one.) What about solutions to an equation $ax\equiv d\mod n$, where $d=\gcd(a,n)$?  This is the question that appeared in our universities last year paper. But it seems very difficult for me like for first part I am able to solve by simplifications I got $x=5\cdot Z +3$ as solution which makes sense and seems fair but for the second one, I have no idea how can I approach that. Can you please help me out with that one. I tried to simplify that by using Euclidean algorithm but still, I didn't get any idea that what actually the solution will be. My final exam is on 2nd of next month and because of covid I am unable to contact in person for any help. So any help from this site will be appreciated. Thank you for looking at this question! I have heard that one ought to turn the pedals at 90rpm. However, I do so much slower, especially while standing, and would like to understand the argument behind this number (or any other number). So:  What is the optimal cadence of a cyclist. Why? Does it depend on the terrain? Does it depend if the rider is sitting or standing upright? What are some possible consequences of deviating too much from the proposed number?  Possible duplicate of , but I didn't find there the "whys" except for "it will grind your knees." However, I find riding upright with slow cadance no more demanding than walking up a hill with a backpack. From :  Error propagation It was common to discuss the &quot;error propagation&quot; properties as a selection criterion for a mode of operation. It might be observed, for example, that a one-block error in the transmitted ciphertext would result in a one-block error in the reconstructed plaintext for ECB mode encryption, while in CBC mode such an error would affect two blocks.  I read  similar post before. And I can understand that in CBC decryption, only two blocks are affected due to error propagation (error in 1 block). But, for the same case in CBC encryption, why are still only two blocks affected? It looks like all the following blocks will be affected. Are objects in PHP passed by value or reference? $\mathbb{F}_p[X]/(X^2+X+1)$ is a field iff $p \equiv 2 \bmod 3$ Let $p$ be a prime. Prove that $\mathbb{F}_p[X]/(X^2+X+1)$ is a field iff $p \equiv 2\bmod3$.    So:   If $p \equiv 2 $ mod $ 3$, I have to show that every element of $\mathbb{F}_p[X]/(X^2+X+1)$ has an inverse.  If $\mathbb{F}_p[X]/(X^2+X+1)$ is a field I have to show $p \equiv 2 $ mod $ 3$. This is a sentence in a book by Rudy Giuliani.     I could ensure my deputies and commissioners were working off the same   page and could carry a coherent message back to their staffs.   Isn't staff a mass noun with no plural when referring to people? Salesforce REST API authentication? I feel like this should be really easy to do, but I can't find anything about it on the web. Is there a way, through either javascript or a java web servlet, to skip the subsequent authentication?  We are trying to use the REST Api in production, but the problem is, that each time you refresh the page in javascript, or delete the cookies in java, you have to login again to salesforce.  Is there some way to do an ajax call or the login in the background or whatever, so that you can have your application connecting to salesforce right away? According to Ohm's Law, if the resistance is zero, the power dissipated by a resistor is unmeaning.  $$P_d = R \times I^2$$  $$I = \sqrt{ \frac {P_d}{R} }$$  Can one calculate the resistance given that power is defined? Only by knowing power, how can one calculate the maximum current of a zero-Ohm resistor?   I'm a bit confused as I've seen there is zero-Ohm resistors with specified power in the market. Looping through array and removing items, without breaking for loop