I just downloaded ubuntu 18.04.3 LTS.   The web site suggests running a given command on the terminal, whereupon the following answer should emerge:  ubuntu-18.04.3-desktop-amd64.iso: OK   However, the answer I get (without any chance or clue as to what to do) is:  shasum: ubuntu-18.04.3-desktop-amd64.iso:  ubuntu-18.04.3-desktop-amd64.iso: FAILED open or read shasum: WARNING: 1 listed file could not be read.   Incidentally, when I tried to install ubuntu 18.04.3 it all went fine until, just before finishing, a message popped up:      "it is not possible to install the bootloader; choose a different   device to install the bootloader on".   No matter which option I chosed (I also tinkered with the boot sequence to no avail), when re-starting my computer, it went to the already installed Windows 10. This OS is on a 256GB SSD drive, while I was recommended (not know the rationale behind it, though) to rather install Ubuntu on the 500GB HDD. Thank you.
I've just downloaded a CD image of Ubuntu. I know the installer has a check CD option, but how can I check that the image is good before burning it to CD?
How many edges does an undirected tree with $n$ nodes have? I am using ArcMap 10.2 and I'm looking for a way to add  a table containing certain fields from select elements from a featureclass to my map. Ive tried the add table option from the attribute table, but it doesn't quite give what I want (the table must be editable to look a certain way).   Are there any options out there for 10.2 like arcpy.mapping.tableview or will upgrading to 10.3 so I can get access to the "graphic table element" function be best? How do I install Ubuntu as the only OS on a MacBook?  That is, I'd like to completely remove Mac OS X and install Ubuntu. I've tried dual-booting, but I've had so much trouble that I prefer to have only Ubuntu installed. I've been looking around and I can't seem to find an automatic (i.e. buzz- or Twitter-like) way to follow users inside Stack Exchange. Why haven't the developers added such a feature? It could help beginner users follow other beginners with the same interests. We would be able to learn from each others' questions and pitfalls. Also, it would reduce double posting. I made up some integrals to do for fun, and I had a real problem with this one. I've since found out that there's no solution in terms of elementary functions, but when I attempt to integrate it, I end up with infinite values. Could somebody point out where I go wrong?  So, I'm trying to determine: $$ \int{\frac{e^x}{x}} \, dx $$  Integrate by parts, where $u = 1/x$, and $v \, ' = e^x$. Then $u \, ' = - 1/x^2$, and $v=e^x$. So,  $$\int{\frac{e^x}{x}} \, dx = \frac{e^x}{x} + \int{\frac{e^x}{x^2}} \, dx$$  Integrate by parts again, $u = 1/x^2$, $v \, ' = e^x$, so that $u \, ' = -2/x^3$ and $v=e^x$. So,  $$\int{\frac{e^x}{x}} \, dx = \frac{e^x}{x} + \frac{e^x}{x^2} + 2\int{\frac{e^x}{x^3}} \, dx$$  Repeat this process ad infinitum to get,  $$\int{\frac{e^x}{x}} \, dx = \frac{e^x}{x} + \frac{e^x}{x^2} + 2 \left( \frac{e^x}{x^3} + 3 \left( \frac{e^x}{x^4} + 4 \left( \frac{e^x}{x^5} + \, \cdots \right) \right) \right) $$  Expanding this gives,  $$\int{\frac{e^x}{x}} \, dx = \frac{e^x}{x} + \frac{e^x}{x^2} + \frac{2e^x}{x^3} + \frac{6 e^x}{x^4} + \frac{24 e^x}{x^5} + \cdots $$  And factoring that gives,  $$\int{\frac{e^x}{x}} \, dx = \frac{e^x}{x} \left(  1 + \frac{1}{x} + \frac{2}{x^2} + \frac{6}{x^3} + \frac{24}{x^4} + \cdots \right) $$  Now, considering the series itself, the ratio between the $n^{th}$ term and the $(n-1)^{th}$ term = $\Large \frac{n}{x}$. Eventually, $n$ will be larger than $x$, so the ratio between successive terms will be positive, so (assuming $x$ is positive), the series diverges, meaning (and I'm sure everybody will cringe upon seeing notation used like this), that:  $$\int{\frac{e^x}{x}} \, dx = \frac{e^x}{x} \left( \infty \right) = \infty $$ opengl storing multiple indices into indices buffer How to boot from non-Ubuntu live ISO images like Fedora or CentOS? Accept Multiple Answers or Split Bounty among Several Users Often more than one person contributes to the community coming up with the final accepted answer to a question. However, it is only possible to accept a single answer. Restricting to one final answer does make sense for the sake of referencing that answer later, but in many cases that answer is the product of the input from several individuals. I would like to be able to decide how much of a bounty goes to different users, or some other mechanism to recognize the contribution of multiple users. Of course I could always upvote their previous answers, but this is really incorrect if their previous answers aren't the complete, final answer I've accepted.  What think you metaSOrs? App question timer shouldn't kick in until submission I attempted to ask a question using the iOS app, but it was rejected due to lack of a required tag. On adding the tag I found that I wasn't permitted to submit the question for another 60 seconds, even though this wasn't a new question.  Is this timer intentional, or should it not kick in for edits of questions not actually accepted by the site? Why is the light reflected at the same angle from mirror? From the school physics I know that the material objects bounce from the plane surface at the same angle, losing some kinetic energy. In the same school I was taught that the light (and waves in general) obeys this principle too.  Obviously, in the case of light the plane surface should be a perfect mirror. But I can't understand how should this work from the quantum point of view. Let's assume that our mirror consists of a single silver atom.  Why should the electrons of this atom re-emit consumed photons at some specific angle? What is the difference between old style and new style classes in Python? What is the difference between old style and new style classes in Python?  When should I use one or the other? Proving that $a \mathbb{Z} \cap b\mathbb{Z} = \operatorname{lcm}(a,b)\mathbb Z$ Given $m \in \mathbb{Z}$, let $m\mathbb{Z}$ denote the set of integer multiples of $m$, i.e. $m\mathbb{Z} := \{mk\mid k \in \mathbb{Z}\}$.   Now let $a,b \in \mathbb{Z}$ with $a,b$ not both $0$. Prove that $a\mathbb{Z} \cap b\mathbb{Z} = \operatorname{lcm}(a,b)\mathbb{Z}$.   I am trying to write a proof for this, but I am unsure of what method to use. Also I am confused by $mk\mid k$, because wouldn't $m=1$ for this to be true. When a land becomes creature, can you kill it? Some lands have an ability to become a creature, but they usually say they are still a land. If a land is a 3/3 creature and a land, can you target and kill it with a  to send it to the graveyard, or does it remain in play as a land? arcpy.env.overwriteOutput = True not working for one dataset It appears that there are at least two questions here on Ask Ubuntu that are similar to this, but neither has been answered.       Text files can be valid under multiple encodings simultaneously. I would like to know the exact encoding gedit uses to decode a given file. Can this be done in the recent versions of gedit?  (I'd like to note that I am aware of other tools that can determine the encoding of a given file. However, I want to know the encoding as detected by gedit specifically) Printing out Stack Overflow/Exchange Q&As including comments? Put a where clause around a stored procedure I cannot edit Prospective PhD contacts potential supervisor but receives no answer after 2-3 emails, what to do? Say a prospective PhD has a high reply rate (90-95%) to first contact emails with potential superviors. He/She has a well thought out e-mail, but a particular professor (here: USA) that is in the top preferences does not reply after two to three e-mails that were sent within a time frame of three months. I also followed the instructions on the professor personal website in the section "prospective PhD students". The student has already contacted some of the advisor students and has received positive feedback about the professor.  Should the student just give up and move on? Should the student keep trying?  Aside from the obvious "I have too many incoming e-mails to answer" or "I am out in the field", what could create a no response behavior from the professor?  I have seen the simplistic answer "move on, bad advisor, doesn't have time, etc". But this seems a contradiction in this case. The PhD students like the professor and say he/she is personable and no e-mail response after a few well written emails. Are there any XSLT processing command line tools? I'm not sure if there's a better place to ask this or not.   Why, at least here in America, is the standard electrical system set up for alternating current (AC) rather than direct current (DC)? I'm just completing a long-distance move and realizing how many DC adapters I have and how many of my devices require DC power:   All of my guitar pedals. My alarm clock. My external hard disks. My USB car HDD dock.   ... and the list goes on. If we're almost constantly having to use DC adapters to convert AC into DC, why isn't the standard DC, other than because people resist change?