I am running Ubuntu 12.04 on an IBM T43 laptop.  I hadn't used the laptop for a few weeks and forgot the password so reset it using the info found on here but now after entering the password the screen just keeps asking for the password again ???  ls -l /home returns dr-x------  I can login OK as 'Guest' and use internet but cannot use my own personal login.  Any idea what is wrong and how to fix it?
My Ubuntu is stuck in a login loop when trying to enter my desktop. When I login, the screen gets black and soon after that the login screen comes back.   I've read that the problem might be caused by an error depending on the graphics, here's my graphics card: ATI Radeon 7670M
Well the question is to solve for $x$ in $$a^x+b^x=c \tag{a,b,c are constants}$$   Well as of me, I tried to put $\ln{}$ on both sides which does not seem to help. Apart from this I don't seem to have any other way to solve it.   I turned to WolframAlpha and the solution which was given was : $$x=\dfrac{-i(2\pi n +\pi)}{\ln{a}-\ln{b}} , {n \in \mathbb{Z}}$$  And if $n=0$ $$x=\dfrac{-i\pi}{\ln{a}-\ln{b}}$$  The only thing I am able to recognize is $e^{i\pi}=1$ ... i guess is used.  Link :   So I see that $x$ is independent of the constant $c$.  So how to solve it? Please help...Thanks!    EDIT - It seems that WolframAlpha is taking $c=0$ as suggested by Donkey_2009. And when i write "Solve for x in a^x + b^x = k" it is not returning anything. So are you guys aware of a method to solve this? Also are you guys aware of any other website/software like WA?    P.S. - Also I see that IF we know the values of $a,b,c$ resulting in something like $2^x+3^x=100$ , then Newton's method is the only method I am aware of that can solve it...  Any other suggestions? Beryllium Vacuum Sphere Boat/Aircraft How to install MariaDB? What is the most stable/safest way to install MariaDB? We have given isosceles triangle $ABC$ with baseline $AB$. Point $M$ is midpoint of AB. Draw perpendicular line to side $AC$ through $M$ which intersects $AC$ in point $H$. Let $P$ be midpoint of $MH$. Show that lines $BH$ and $CP$ are perpendicular to each other.  I also have "hint": Construct height $BD$ to side $AC$ and look at the triangles $ABD$ and $MCH$.  Analytically there is no problem but I get stuck in geometrical approach to solution. Ignoring invalid input features with Intersection tool in QGIS? In QGIS 2.18, when I used the Vector > Geoprocessing Tools > Intersection tool, I was able to check an option which said "Ignore NULL geometries [optional]".  Now I've downloaded QGIS 3.2 and that option no longer exists. But when I try to create the intersection between two layers I'm working on, I get a message saying that there is an invalid geometry somewhere and that I should either fix it it or "change the Processing setting to the 'Ignore invalid input features' option."   But that option doesn't exist! Or if it does exist, I just can't find it anywhere.  Does anyone know how/where to change this setting in QGIS 3.2? I'm trying to compose a cone in Inkscape, embedding text, image (after converted in vectors):   But, after importing in Blender, here is what I get:   You see then that something went wrong, but I don't know what. Please your advise is welcome !  JF "I'm lovin' it" How normal-sounding is the slogan "I'm lovin' it" to native ears?  I know it sounded quite odd to me when I first heard it — and it still sometimes does —, but I can't even tell why. Sure, love is supposedly a stative verb, but it's being used in progressive aspect all the time without sounding weird at all (lots of songs come to mind, e.g. ). It's only this particular slogan that somehow doesn't quite work for me. I would expect that to be totally on purpose — it's advertising, after all —, but Wikipedia  any objections from native speakers (as it does with "" and ""). So I'm asking the native speakers of this community: does "I'm lovin' it" sound completely natural to you? Just a bit off? Completely weird? Why? Can a mangaka continue another mangaka's manga? There are plenty of manga that never had an ending for many reasons. For example, High School of the Dead's mangaka, Daisuke Satou, . Some mangaka also cannot continue their work because of health problems, as well as other reasons. Say the original mangaka either prepared or did not prepare an ending himself/herself, can another mangaka continue their work? Has this ever happened before? Tracking Object Position - Firing on a Trajectory XML attribute vs XML element At work we are being asked to create XML files to pass data to another offline application that will then create a second XML file to pass back in order to update some of our data. During the process we have been discussing with the team of the other application about the structure of the XML file.   The sample I came up with is essentially something like:  &lt;INVENTORY&gt;    &lt;ITEM serialNumber="something" location="something" barcode="something"&gt;       &lt;TYPE modelNumber="something" vendor="something"/&gt;     &lt;/ITEM&gt; &lt;/INVENTORY&gt;   The other team said that this was not industry standard and that attributes should only be used for meta data. They suggested:  &lt;INVENTORY&gt;    &lt;ITEM&gt;       &lt;SERIALNUMBER&gt;something&lt;/SERIALNUMBER&gt;       &lt;LOCATION&gt;something&lt;/LOCATION&gt;       &lt;BARCODE&gt;something&lt;/BARCODE&gt;       &lt;TYPE&gt;          &lt;MODELNUMBER&gt;something&lt;/MODELNUMBER&gt;          &lt;VENDOR&gt;something&lt;/VENDOR&gt;       &lt;/TYPE&gt;    &lt;/ITEM&gt; &lt;/INVENTORY&gt;   The reason I suggested the first is that the size of the file created is much smaller. There will be roughly 80000 items that will be in the file during transfer. Their suggestion in reality turns out to be three times larger than the one I suggested. I searched for the mysterious "Industry Standard" that was mentioned, but the closest I could find was that XML attributes should only be used for meta data, but said the debate was about what was actually meta data.  After the long winded explanation (sorry) how do you determine what is meta data, and when designing the structure of an XML document how should you decide when to use an attribute or an element? How to prove the divisibility rule for $3\, $ [casting out threes] The divisibility rule for $3$ is well-known: if you add up the digits of $n$ and the sum is divisible by $3$, then $n$ is divisible by three.  This is quite helpful for determining if really large numbers are multiples of three, because we can recursively apply this rule:  $$1212582439 \rightarrow 37 \rightarrow 10\rightarrow 1 \implies 3\not\mid 1212582439$$ $$124524 \rightarrow 18 \rightarrow 9 \implies 3\mid 124524$$  This works for as many numbers as I've tried.  However, I'm not sure how this may be proven.  Thus, my question is:     Given a positive integer $n$ and that $3\mid\text{(the sum of the digits of $n$)}$, how may we prove that $3\mid n$? It appears that on Server Fault and Super User, the navigation bar and question title have suddenly become misplaced. The same does not occur on SO and mSO, nor on any of the other SE sites I spot-checked.  This is being seen in both Chrome and Firefox and just began occurring within the last few minutes.      What it should look like:      While this was fixed for a few hours, it has returned as of 22:05. How do I set environment variables from Java? How do I set environment variables from Java?  I see that I can do this for subprocesses using . I have several subprocesses to start, though, so I'd rather modify the current process's environment and let the subprocesses inherit it.  There's a System.getenv(String) for getting a single environment variable. I can also get a Map of the complete set of environment variables with System.getenv(). But, calling put() on that Map throws an UnsupportedOperationException -- apparently they mean for the environment to be read only. And, there's no System.setenv().  So, is there any way to set environment variables in the currently running process?  If so, how?  If not, what's the rationale?  (Is it because this is Java and therefore I shouldn't be doing evil nonportable obsolete things like touching my environment?)  And if not, any good suggestions for managing the environment variable changes that I'm going to need to be feeding to several subprocesses? ls command very slow after deletion of thousand files on a directory I have a dir under /home/myuser dir which an application stores and deletes millions of temporary files. When I do ls on this dir (now it only has a hundred files only) it is too slow (actually I do not get any output for many minutes). After some google search and doing:  ls -dl ~/mydir/   I get this  drwxrwxrwx 2 myuser myuser 160108544 Oct 12 11:31 /home/myuser/mydir/   which basically means I have to re-index directory entries for this directory (if I understood correctly). How do I do force such a re-indexing on this dir? Suppose $T$ is the subset of $M_2(\mathbb{Z})$ of lower triangular matrices, those of form $\begin{pmatrix} a &amp; 0 \\ b &amp; c\end{pmatrix}$. So $T$ is a subring. Now I know that the ideals of $M_2(\mathbb{Z})$ are all of the form $M_2(I)$ for $I$ and ideal of $\mathbb{Z}$.   However, is there a nice way to describe all the ideals in $T$ specifically, or does it not behave quite as nicely? Product of Non-Disjoint Cycles I am trying to learn how to find the product of non-disjoint cycles, as you may have guessed from the title. I have the basic idea, but I do not understand it entirely.  I am trying to find $(1352)(256)$ and $(1634)(1352)$, multiplying from right to left.  Please give me some hints/suggestions.  Thank you. Can I mix sources from different ubuntu versions? As we know that we are using  for installing packages and repositories configuration file located at /etc/apt/sources.list.  I am using Ubuntu 12.10 (Quantal Quetzal) which reaches . That means no updates or support. So, the question is, can I use sources.list file from another version, say Ubuntu 12.04 LTS, and will it negatively affect the system. Which is correct: "he don't" or "he doesn't"? Which one is correct in a sentence?        He don't    He doesn't      I guess "he doesn't" should be correct because he is third person singular but I've seen some people using do with he. Which one is correct? Prove there is an increasing sequence ($s_n$) of points in $S$ such that $\lim s_n = \sup S$. As the title says. How do I get from  $\frac{n}{\varphi(n)}$ to $\sum\limits_{d \mid n} \frac{\mu^2(d)}{\varphi(d)}$?  I know that $$\frac{n}{\varphi(n)}=\frac{\sum\limits_{d \mid n} \varphi(d)}{\sum\limits_{d \mid n} \mu(d)\frac{n}{d}},$$ and I suspect it is down this road I should go. But I get totally confused by the sums and I have no clue on how to divide them and "combine" them into one again. Any hints or advice would be much appreciated.