im a JS beginner and I'm a bit confused of this code: let array = [&quot;string1&quot;, &quot;string2&quot;] let arrayCopy = array array[0] = &quot;changedString&quot; console.log(arrayCopy) // Returns Array [&quot;changedString&quot;, &quot;string2&quot;]  Why is the assignment of Array also mutating the copy?
The primitive types (number, string, etc.) are passed by value, but objects are unknown, because they can be both passed-by-value (in case we consider that a variable holding an object is in fact a reference to the object) and passed-by-reference (when we consider that the variable to the object holds the object itself).  Although it doesn't really matter at the end, I want to know what is the correct way to present the arguments passing conventions. Is there an excerpt from JavaScript specification, which defines what should be the semantics regarding this?
I would like to take control of my app on an iOS device (mostly an iPhone) from my MacBook Pro or Windows, doesn't matter which one.  I know that it can be accomplished via Veency, and that's exactly what I need - but I do NOT want to jailbreak my iPhone.  Is there a similar legal alternative?  If not - is it something I could develop perhaps, or will I run into some SDK limitations for such a thing? I'm interested in quantum mechanics book that uses high level mathematics (not only the usual functional analysis and the theory of generalised functions but the theory of pseudodifferential operators etc, certainly the modern mathematics). If there isn't something similar please give me a reference to the book that is strictly supported by mathematics (given a set of mathematically descripted axioms author develops the theory using mathematics as a main tool). When A and B are positively related variables, can they have opposite effect on their outcome variable C? A is positively related to B.  C is the outcome of A and B, but the effect of A on C is negative and the effect of B on C is positive.  Can this happen? How much meat should I serve per person? How can I remove a trailing newline? What is the Python equivalent of Perl's chomp function, which removes the last character of a string if it is a newline? Vertical line only in one part of a table I need some help on  putting a vertical line in the second part of the table, I don't know how to do it since the tabularx I declared does need to have that only in the second part. The code I used is:  \begin{tabularx}{\linewidth}{|XX|} \hline \multicolumn{2}{|c|}{\textbf{title name}}\\ \hline something: &amp; else \\ something: &amp; else \\ something: &amp; else \\ \hline \multicolumn{2}{|c|}{bla bla blah}\\ \hline title text: &amp; description 1 \\ title text: &amp; description 1 \\ \hline \end{tabularx}   And the render of the table looks like this:    I just need a \vline between title text and description (it I use \vline it works only for the first line but the description text and sometimes the title, are few lines long). Automatically prefer Ethernet over WLAN How to Straighten Curved UVs into Straight Belt Open source computer algebra systems for general relativity I would like to use an open source computer algebra system (CAS) for research in general relativity. Kindly suggest a good choice between Ipython and Sage. I am more interested in the theoretical aspect rather than numerical computations. Why aren’t my villagers breeding? I’ve got one villager up 7 blocks surrounded with 6 doors. On ground level I have villagers who are supposed to breed. They are willing, their inventories are full of potatoes, and I’ve been sitting here for hours.  Hearts are popping up above their heads but nothing happens. I am playing on Xbox One. came in Low Quality Posts review which was  as "This is commentary on another post, not an answer" by *. But the comment was added 5 times automatically on behalf of that user.        First four comments' time is 2013-07-15 10:23:18Z while the last one's time is 2013-07-15 10:23:19Z. Those comments are still exist. 10K+ users can see that.  Is this a bug or something else?  * Because the comment is added on behalf of that user. In a closed system, I know the rider wouldn't be able to change the combined center of gravity of the system by moving his weight around. If he pushes the bike to lean to the right, he would go to the left by the amount that would keep the combined cog the same.  But a bike with tires and a road under it is not a closed system, the tires wouldn't let the lower part of the bike left or right when tryingo to initiate lean. Does this mean it is possible to push with your bodies inertia to the bike, and the combined cog will be changed? I thing if you do so above the cog of the bike, you could, but I am not sure.  Edit: My question is not about if you can move the center of gravity of the bike at all. My question is about if can you change the combine cog of the system by moving around on the bike?  English is not my mother tongue, sorry for the confusion How do you empty the buffers and cache on a Linux system? Is it possible for some integer $n&gt;1$ that $2^n-1\mid 3^n-1$ ?   I have tried many things, but nothing worked. Why is my membership length only "Six months"? I was viewing the  and I noticed that I've apparently only had my account for six months, which is news to me... I opened my first site account here in February of 2014.  My account is much older than this, what's causing this bug?  To add some detail... On the per-site list, it does line up the &quot;member for X&quot; text with my actual membership time on that site. For example, when I look at the Meta Stack Exchange leaderboard, it shows me as a member for 2 years, 10 months. This is expected.  Update. With some work, today, I've managed to exceed my Interpersonal Skills hat count of with my Meta Stack Exchange hat count. This has changed my account age to match my MSE account age...  Still not reflective of my actual age... but better. I was asked this question during an interview for a trading position with a proprietary trading firm. I would very much like to know the answer to this question and the intuition behind it.  Amoeba Question:  A population of amoebas starts with 1. After 1 period that amoeba can divide into 1, 2, 3, or 0 (it can die) with equal probability. What is the probability that the entire population dies out eventually? Determine resultant velocity of an elastic particle-particle collision in 3d space So I have two particles that have collided in 3 dimensional space. I want the particles to rebound off of each other in an elastic manner. How do I determine the resultant velocity vector if I know: Both particles' initial velocity vector, their masses, and their initial position vectors relative to the origin.  I tried to follow the instructions on  but I am not sure how to make their equations work without polar coordinates / how to translate my data to polar coordinates.  Also, if you answer my question in terms of polar coordinates, can you explain which angle is theta and which is phi? Since there are 2 different conventions, I am not really sure which angle is being referred to in the explanation on the aforementioned website.  EDIT: This isn't for a class. I'm writing a physics engine for a gravity simulation I am making using Unity. I haven't taken kinematics since I was in high school, which is why I am so rusty. The method signature of a Java main() method is:  public static void main(String[] args){     ... }   Is there a reason for this method to be static? Combinatorial proof of an identity with squared binomial coefficients Is it true that $\sum_kk\binom{n}{k}^2=n\binom{2n-1}{n-1}$? (I proved it using generating functions). Could you help me to prove it combinatorially? please I always use align in my documents, and avoid equation. Is there anything wrong with that? My reasoning behind this: align > equation, so why not use it?