In a = [1, 2] and b = [1, 2], a == b is True and a is b is False but could someone please explain how a == [1, 2] returns True
My  has failed me.  In Python, are the following two tests for equality equivalent?  n = 5 # Test one. if n == 5:     print 'Yay!'  # Test two. if n is 5:     print 'Yay!'   Does this hold true for objects where you would be comparing instances (a list say)?  Okay, so this kind of answers my question:  L = [] L.append(1) if L == [1]:     print 'Yay!' # Holds true, but...  if L is [1]:     print 'Yay!' # Doesn't.   So == tests value where is tests to see if they are the same object?
What is the sum of the 'second half' of the harmonic series?  $$\lim_{k\to\infty}\sum\limits_{n=k+1}^{2k}{\frac{1}{n}} =~ ?$$  More precisely, what is the limit of the above sequence of partial sums? Find the volume inside the paraboloid $x^2+4z^2+8y=16$ and on the positive side of xz-plane No answer was given for this question, so wanted to confirm my answer. Steps followed for solving:  V=$4\int_0^2\int_0^{\sqrt{16-4z^2}}(2-\frac{x^2}{8}-\frac{z^2}{2})dxdz$  After solving this I got V = $8\pi$. Is this answer correct? Security of GCM if Implemented with Stream Cipher instead of Block Cipher Suppose $\displaystyle P(x,y)$ a polynomial in the variables $x,y$.   For example, $\displaystyle x^4$ or $\displaystyle x^3y^2 + 3xy + 1$.  Is there a general method which allows us to evaluate the indefinite integral     $$ \int P(\sin x, \cos x) \text{d} x$$   What about the case when $\displaystyle P(x,y)$ is a rational function (i.e. a ratio of two polynomials)?   Example of a rational function: $\displaystyle \frac{x^2y + y^3}{x+y}$.    This is being asked in an effort to cut down on duplicates, see here:   and here: Links to the Wayback Machine are broken in chat transcript is an example of the bug. It looks like this in regular chat:  That link points to: http://web.archive.org/web/20080409050311/http://personalpages.manchester.ac.uk/staff/daryn.lehoux/Tropes.pdf  In the transcript, it looks like this:  That link points to: http://web.archive.org/web/20080409050311/%3Ca%20href=  ... which doesn't work so well! Could this be fixed? I'm not sure if this impacts links to elsewhere. When I open this ssh tunnel:  ssh -nXNT -p 22 localhost -L 0.0.0.0:8984:remote:8983   I get this error when trying to access the HTTP server running on localhost:8984:  channel 1: open failed: administratively prohibited: open failed   What does this error mean, and on which machine can you fix the problem? Changing left margin in itemize environment of beamer class I can't figure out how to line up the symbols of an itemize environment in beamer with the left part of the main text. In other words, I would like to supress the left margin in beamer itemize lists.  It would be nice if the solution worked with any itemize label defined with  \setbeamertemplate{itemize item}[]   In order to make myself clearer, what beamer produces by default is something like:  Main text. Main text. Main text...    * Item 1    * Item 2    * Item 3    ....   and the desired result is   Main text. Main text. Main text... * Item 1 * Item 2 * Item 3 .... Tag links in tag excerpts not shown properly If a tag excerpt contains a link to another tag with the [tag:foobar] syntax, this link is not properly shown in every context. For an example see . The link is shown as [tag:school-libraries] but it should be  or at least "school-libraries". I know that there is a precise solution of the equations:  \begin{align}     x + a &amp; = 0 \\     x^2 + a\cdot x + b &amp; = 0 \\     x^3 + a\cdot x^2 + b\cdot x + c &amp; = 0 \\     x^4 + a\cdot x^3 + b\cdot x^2 + c\cdot x + d &amp; = 0 \end{align}  Why there is no solutions for equation of degree $\ge 5$? How can I tell how long (more or less) it will take me to complete a game? I'm going down my huge backlog of unplayed Steam games and I'm thinking the best way to tackle the list is to go through the shortest games first and then concentrate on the 20+ hour ones. I'm wondering if there's a website or something else that has an estimated amount of gameplay time for games.   Is there anything like that? How can I install MonoDevelop v4 on 12.04? I am using Ubuntu 12.04. I can install v2.8.6.3 of Monodevelop from software center but I need at least v3 to use Monogame v3 or higher. Can anyone point me in the right direction please?   Thanks Force NTFS permissions inheritance for newly created files Let $L$ be a linear operator on a complex vector space $V$, how to show that eigenvalues of $L^\dagger L$ are positive? I guess this might be a statement taught in a functional analysis class or an advanced linear algebra class? Possible Duplicate:          Can anyone offer me advice on how to clean my camera's sensor?   Should I do this myself, or take the camera to a professional? Is it precarious, or easy with the right amount of care?   I have a Nikon D3000 that has a small dot off-center of the sensor. I believe it is dirt, and I would like to remove it. I'm tempted to use a cotton-bud, but I'm afraid that I might damage the sensor.  The dot appeared after a trip to a tropical area where the camera became wet. I took the lens off and a lot of moisture, and possibly some dirt, went into the camera. The lens became fogged-up.  When I returned from my trip I ran a hair dryer for (air only, without heat) 10 minutes through the battery compartment, believing this would circulate around and dry the camera. Consequently, I noticed many speckled dots around the sensor. I also believe there's a subtle but persistent haze when I look through the lens, but I could be wrong.  It's worth noting that the photos are fine, with no evidence of distortion or blurring. The camera is now dry and it's been months since this happened. But the dot on the sensor has been there since, like an itch I can't rub. Performing Point Distance analysis using Basic level license of ArcGIS Desktop? I am using ArcView (ArcGIS Desktop Basic) 10.1 and I need to perform a point distance analysis.   What are the steps to determine the distance from A to B-Z, B to A-Z, C to A-Z, etc? Can I put 700c tires on rims made for 27 x 1.25"? Roots of $\,ax^2+bx+c\,$ are irrational if $a,b,c$ are odd integers How would I show the following.  For all odd integers a,b, and c if z is a solution of $ax^2+bx+c=0$ the z is not rational.  How would I show this? This is what I did  Let a be an odd integer then for a integer k it has the form $a=2k+1$  then $b=2t+1$ for if c integer.  then $c=2r+1$ if s is an integer then I do  $(2k+1)(x)^2+2t+1(x)+(2r+1)=0$  But I find my self stuck on what to do any hint are appreciated. Why does the symbol for the multiplication operation change shape? Why does the "$\times$" used in arithmetic change to a "$\cdot$" as we progress through education? The symbol seems to only be ambiguous because of the variable $x$; however, we wouldn't have chosen the variable $x$ unless we were already removing $\times$ as the symbol for multiplication. So why do we? I am very curious. It seems like $\times$ is already quite sufficient as a descriptive symbol. UEFI machine doesn't boot Ubuntu through NVRAM bootcatalog. How to fix? Where are packages stored installed with APT in Ubuntu 16.04?