how to evaluate the integral $\int_0^1 \frac{\ln(1+x)}{x} dx$？
Finding $ \int^1_0 \frac{\ln(1+x)}{x}dx$
Where to find cross section data for $e^{-}$ + $p$ $\longrightarrow$  $p$ + $e^{-}$ ?  does not include it. Can I ignore coefficients for non-significant levels of factors in a linear model? After seeking clarification about linear model coefficients  I have a follow up question concerning non-signficant (high p value) for coefficients of factor levels.  Example: If my linear model includes a factor with 10 levels, and only 3 of those levels have significant p values associated with them, when using the model to predict Y can I choose to not include the coefficient term if the subject falls in one of the non-signficant level?  More drastically, would it be wrong to lump the 7 non-significant levels into one level and re-analyze? How to combine measurement error with statistic error What is the lifespan of an SSD drive? Are SSDs comparable to HDDs for reliability and is there published research on this?  Also are all SSD manufacturers at a similar 'reliability level'? How would you implement an LRU cache in Java? Please don't say EHCache or OSCache, etc. Assume for purposes of this question that I want to implement my own using just the SDK (learning by doing). Given that the cache will be used in a multithreaded environment, which datastructures would you use? I've already implemented one using  and , but I'm curious if any of the new concurrent collections would be better candidates.  UPDATE: I was just reading through  when I found this nugget:     If you need constant-time access and want to maintain the insertion order, you can't do better than a LinkedHashMap, a truly wonderful data structure. The only way it could possibly be more wonderful is if there were a concurrent version. But alas.   I was thinking almost exactly the same thing before I went with the LinkedHashMap + Collections#synchronizedMap implementation I mentioned above. Nice to know I hadn't just overlooked something.  Based on the answers so far, it sounds like my best bet for a highly concurrent LRU would be to extend  using some of the same logic that LinkedHashMap uses. I've just installed MariaDb on a fresh Ubuntu Gnome and ran  afterwards where I set a decent admin password, removed the anonymous user etc.  Afterwards I realized some strange behavior regarding the admin password:   If I try to login from my normal user account using the command mysql -u root -p I always get an error: ERROR 1698 (28000): Access denied for user 'root'@'localhost' I'm pretty sure I entered the correct password which I set with  earlier... When I run the command from root using sudo mysql -u root -p, I always get access to the database, no matter which password I actually enter...   Is this normal behavior, am I doing anything wrong or have I somehow screwed up the installation? I'm working on this problem from Elementary Analysis by Ross which is intuitive when sketched but keeps stymieing me when I try to write it out.  Let $f$ be a continuous function on $[a,b] \subset \mathbb{R}$. Define $f^\star (x)$ as:  $$ f^\star(x) = \sup \{f(y)\mid a \leq y \leq x \} $$ Prove that $f^\star$ is a continuous increasing function on $[a,b]$.  Things I've figured out: (these are mostly trivial)   $f$ is uniformly continuous on $[a,b]$. Since $[a,b]$ is closed and bounded there exists some $c \in [a,b]$ such that $f(c) \geq f(x)\ \forall x \in [a,b]$. (In words: the supremum is actually attained.) If $c \in [a,b]$ is as above, then $f^\star$ is constant (and hence continuous) on $[c,b]$ (which is possibly a singleton).   This seems completely obvious when you actually draw a continuous function but translating that to a formal proof eludes me... What graphics packages are there for creating graphics in LaTeX documents? I want to subtract a constant number from my data to get new data file. For example, I want to subtract  10 from my data.   data.txt  Id  a   b   c   d   e 1   1   2   3   4   5 2   2   3   4   5   6 3   3   4   5   6   7 4   4   5   6   7   8 5   5   6   7   8   9 6   6   7   8   9   10 7   7   8   9   10  11 8   8   9   10  11  12 9   9   10  11  12  13 10  10  11  12  13  14 11  11  12  13  14  15 12  12  13  14  15  16 13  13  14  15  16  17 14  14  15  16  17  18   Required output:  out.txt   Id  a   b   c   d   e 1   -9  -8  -7  -6  -5 2   -8  -7  -6  -5  -4 3   -7  -6  -5  -4  -3 4   -6  -5  -4  -3  -2 5   -5  -4  -3  -2  -1 6   -4  -3  -2  -1  0 7   -3  -2  -1  0   1 8   -2  -1  0   1   2 9   -1  0   1   2   3 10  0   1   2   3   4 11  1   2   3   4   5 12  2   3   4   5   6 13  3   4   5   6   7 14  4   5   6   7   8 Ask question post button remains disabled I've noticed this twice in the last ~2 weeks or so. The &quot;post your question&quot; button can remain disabled for some reason even when your question is shown as &quot;ready to publish&quot;. I.e., you've gotten to the &quot;review&quot; page after the initial edit. If I remember correctly, one case was on Stack Overflow, and the other was on . I'm not sure what exact scenario leads up to this. I haven't paid attention to the button until the last step when I'm ready to click it. The workaround has been to reload the page. (I copied my content for safe-keeping first.) This works, and the button then shows up as active. Afterwards, however, on both occasions, it forced me through the &quot;are you a human&quot; verification.  Update - this question itself did not exhibit this, nor did it do the .  Update - I'm using Chrome on Windows and am not sure what version it was when this happened.  It has  installed, but there aren't any scripts for any Stack Exchange sites.  It has  installed.  The virus scanner on the PC I probably was using was Variational Derivation of Schrodinger Equation Understanding 74LVC245 datasheet and current source/sink I'm using a SN74LVC245A () to shift 5V TTL down to 3.3V so I can read the signals with a Raspberry Pi.  However I am getting really weird results (a 60Hz input signal is picked up by the Pi at anything between 110Hz and 320Hz) and I'm really confused about how to read the datasheet to figure out whether I need pullup or pulldown resistors.  The datasheet says on page 4 the "high-level output current" is -24mA, and the "low-level output current" is 24mA.  So to me this means that when the device is outputting a high signal, it is able to sink 24mA of current (since outputting a negative amount of current suggests the current is going into the device instead.)  But then if you're outputting a positive voltage, isn't that sourcing current?  Why is the figure listed as a negative value?  Is anyone able to explain what these figures actually mean?  When I disconnect the 74LVC245 output from my GPIO pin, I still get weird signals from the floating input pin so I am assuming this means the 74LVC245 output is also floating in one state, but I don't know in which state it is (i.e. is it left floating on a high output signal or a low one?)  It doesn't really make sense to be floating on a high output signal since it's a level converter and the whole point is to maintain the correct 'high' voltage, so do I need pulldown resistors to handle the low output?  If so, why does the datasheet seem to suggest the chip can both source and sink current?  (In my mind, source current means the device can output a current with a positive voltage, while sinking current means the device takes in anything and connects it to GND, so perhaps that is where I am going wrong.)  Anyway I'm quite confused so any clarification would be much appreciated! Revert new tab page behavior in Google Chrome 29+ I don’t like the behavior of the new tab page in Google Chrome 29+. How can I restore the old behavior?  The new tab page (if you have Google set as the default search engine) now shows the Google logo (or, apparently, the doodle of the day if there is one), a search box, and a few recently visited websites. It also added an Apps button to my favorites bar, seemingly the only way to access my apps page, which has easy access to things I use regularly (Calendar, Gmail, Docs, G+, Facebook, Feedly, Google News, Netflix, Play Music, Pandora, Drive, Keep, etc.) I don’t like this behavior. I actually don’t mind having the logo of the day and search box, but I want my apps linked to on my new tab page.  Is there any way to get the old behavior back? I checked the settings and it doesn’t seem like it’s possible to set chrome://apps to be the new tab page (which would restore the old behavior) or to configure the new new tab page to display apps instead of recently visited sites. Inequality $\left(a-1+\frac{1}b\right)\left(b-1+\frac{1}c\right)\left(c-1+\frac{1}a\right)\leq1$ How do I install a Fortran 77 compiler? I have just installed 12.04 LTS on my laptop and I'm kinda new in this. I am required to write some program in Fortran 77 and I need a Fortran 77 compiler. I have tried installing g77 as described in the Ubuntu website but was unable to do so. I have typed in the following in terminal:  sudo apt-get install g77   and get the following:  Reading package lists... Done Building dependency tree        Reading state information... Done Package g77 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'g77' has no installation candidate   May I know what is the problem? I have tried searching g77 in the software center but apparently it is not there. Does this mean it is not available for 12.04?  I'm currently using an Asus K43S laptop with Intel Core i5-2450M processor and my Ubuntu is installed alongside Windows. It seems that most people who use the ignored tags feature end up with a fairly long list of those tags.  Although , it is sometimes necessary to add new ignored tags manually (typically when adding some-tag*).  It would be a lot easier if the add box was above the long list of ignored tags rather than below. I suppose the same would apply to the favorites tags for consistency's sake. Why does 'g' sometimes read as 'j'? Most words with 'g' read as 'g'   Geek Goose Goods Goal   But sometimes 'g' reads as 'j'   Gymnastics Genesis Genius Genetic   And in the middle of a sentence, compare:   Log Logistics   Or   Frag Fragile Mark read notifications as unread In the Android app, can we have some option to mark a read notification to unread? I know that this option is not available in the web version of Stack Exchange sites. But sometimes I open the notification in the app and it opens the post, but sometimes I can't see the exact reply to my comment or where my name is mentioned using the app.   And I want those comments to be read from the web version of the Stack Exchange site. Sometimes I forget about replying to a comment since the notification is already marked as read. So I want to mark the notification as unread and have it as a new notification displayed in the mobile app and the web version too. How to change language of a specific application? What would be the effects of warp collisions? Triggered by a  I was wondering what actually would happen to a ship (e.g. the Enterprise-D NCC-1701) that collides with a stationary object such as a) another ship of a similar configuration or b) a gigantic structure like a moon or even a planet.  We know the deflector is supposed to keep interstellar dust (not to be confused with ordinary dust, which is a different thing) from ripping large holes in the ship.  At first, one thinks "Obvious. ." But does it really? Would the deflector manage to actually deflect both masses? If not, where is the threshold of what a deflector can handle? Would the ship maybe tunnel right through the object, because of wibbly-wobbly space wobblification by the warp field? It does do some weird things to the space right in front and behind the vessel.  Important remark: We cannot approach this with what we know about physics at all. For all intents and purposes, both ships must measure the other ship travelling faster than light, resulting in it having infinite (or rather undefined) mass and by extension momentum. If we start with that reasoning any ship jumping to warp would suck in the entire universe (it takes a moment, but think about it). So, obviously we cannot apply our intuition (even our relativistic intuition) here.