Abstract methods in Python
Is it possible to make abstract classes in Python?
Solving $x - a \log(x)=b$ Let $a&gt;0$ and $b \in \mathbb{R}$: Assume there exists an $x &gt;0 $ s.t. $$x - a\log(x) = b$$ holds. How can it be determined in closed-form? What are the biggest changes between UA Ranger and PHB Ranger? Word for the behavior of people who complain at everything you do What is the first movie to show this hard work message at the very end? What is the first movie to show this hard work message at the very end? $a_{n+1}=\log(1+a_n),~a_1>0$. Then find $\lim_{n \rightarrow \infty} n \cdot a_n$ Changing back button in iOS 7 disables swipe to navigate back Subsurf on a crown. How can I smooth some edges and keep others sharp? How can I smooth all crown but don't smooth the top of the crown? I did a subdivision surface, but this didn't work. All crown became smooth and changed form. Suppose $p$ is a prime number such that $(p-1)/4$ and $(p+1)/2$ are also primes. Show that $p=13$ Suppose $p$ is a prime number such that $(p-1)/4$ and $(p+1)/2$ are also primes. Show that $p=13$.   My approach:   Since $p$ is prime, it is of the form $6k+1$ or $6k-1$. Now if $p$ is of the form $6k-1$ then $(p+1)/2 = 3k$ which is not possible as $3|3k$.   So $p$ is of the form $6k+1$. Now $(p-1)/4 = 3k/2$ so $2\mid k$. So $p$ is of the form $12k+1$. But now, how to prove $k=1$?  Please help! arbitrary large finite sums of an uncountable set. "Missing return statement" within if / for / while Is Poly1305 an information-theoretically secure MAC? I'm listing some items for sale online, and have taken a bunch of pictures with my iPhone.  About half-way through the process, iPhoto '11 stopped downloading new photos into its local Photo Stream.  I've quit iPhoto and re-opened it.  I've gone into the Photos app on my iPhone and confirmed all the pictures are there.   Is this normal behavior? Is there any way to tell iPhoto to download my pictures? How do I set up SSH so I don't have to type my password? How do I set up SSH so I don't have to type my password when connecting to a host? Multiple solutions for a particle in an infinite potential well I am starting to learn about quantum mechanics and was wondering about the solutions to a question about a particle in an infinite potential well of length $L$.  The solutions are: $$\psi_n(x) = \sqrt{\frac{2}{L}}\sin\left(\frac{\pi n x}{L} \right)$$  And I was wondering what is the meaning of $n$. Isn't there supposed to be only one wave function? In that case, $\Psi = \sum_{n=1} ^\infty a_n \psi_n$, but what are the $a_n$? Or maybe it is probabilistic, and we don't know which $\psi_n$ the particle is currently in? I have a very simple jQuery Datepicker calendar:  $(document).ready(function(){     $("#date_pretty").datepicker({      }); });   and of course in the HTML...  &lt;input type="text" size="10" value="" id="date_pretty"/&gt;   Today's date is nicely highlighted for the user when they bring up the calendar, but how do I get jQuery to pre-populate the textbox itself with today's date on page load, without the user doing anything?  99% of the time, the today's date default will be what they want. K-means - comparing solutions with SSwithin elbow-method: minimum "too early", or non-monotonic curve How can I prevent installation of a specific package on Linux Mint? Solve $\frac1x+\frac1y=\frac1{pq}$ For $x,y\in\mathbb{N}$ how many ordered pairs $\left(x,y\right)$ satisfy   $\dfrac{1}{x}+\dfrac{1}{y}=\dfrac{1}{pq}$ where $p,q$ are distinct primes? passthrough graphics card to virtualbox So I'm trying to get my laptops NVIDIA fx 880m to pass to a virtual box running window seven on a linux mint 17 install.  So far everything seems to be (maybe) heading in the right direction:  the device passed through happily, when I booted the virtual box it installed a bunch of new drivers, but when I try to install the NVIDIA driver on the guest it can't find the card. I looked under the device manager and there's no listing for the nvidia card under the pci bus, my guess would be that I need to disable it in the host so that it can be passed through to the guest (the virtual box manual said they can't be shared) but I'm not sure how to do so. Can anybody help with this? This question does not seem to me to be a duplicate of , because here the given solution was that it was not possible with a windows host, however in this case the host is linux When is the finalize() method called in Java?