Finding slope of polyline in QGIS?
Can I create a TIN from contours lines (shp) in QGIS?
Sum over all non-evil numbers I'm working on the following contest math problem:     Define an evil number to be any positive integer that contains the   digit $9$. Show that      $$ \sum_{x} \frac{1}{x} &lt; 80 $$      where the sum is over all non-evil positive integers $x$.   I'm very confused on where to begin. Initially, I tried to consider this sum as part of the sum of $1/x$ over all positive integers, namely by noting that  $$ \sum_{n=1}^{\infty} \frac{1}{n} = \sum_{x} \frac{1}{x} + \sum_{y} \frac{1}{y} $$  where the first summation on the right side is the same as in the problem statement and the second is the sum over all evil numbers. However, I can't seem to find a way to use this since the sum of the left diverges.  Could anyone lend a helping hand? Where can I find sugar cane? I played several hours a started three different worlds in Minecraft, but I have never found any sugar canes. I read on Minecraft wiki to search near water but still no luck. Do you have more hints? Is it possible to re-create an environment that allow sugar canes to naturally grow? What does unwrapping a model do and why is it important? Any situation, any time; this person has always something negative to say about it.  It should be a noun or an adjective to describe a person who is a damp cloud walking over every sunshine situations at the cubicle, hoping to drench other people with his miserable comments.    I considered "sourpuss" but would prefer something more important sounding, like "misogynist." Prove that $ \int _a^b\:f\left(x\right)\:\:dx\:=\:\int _a^b\:f\left(a+b-x\right)\:\:dx $ This is the prove- $y=a+b-x$. Then $dy/dx=-1$ and thus $$\int_a^bf(a+b-x)dx= \int_b^a-f(y)dy = \int_a^bf(x)dx$$  But I dont understand the last part of this - Why ? $$\int_b^a-f(y)dy = \int_a^bf(x)dx$$  I know that $\int_b^a-f(y)dy = \int_a^bf(y)dy $. But something is not clear to me. What should I do if a question has changed since I answered it? The other members vote my answer down because it actually doesn't answer the current question.  This kind of editing sometimes happens with  where the OP keeps adding new questions, making my pre-existing answer now incomplete.  But another pattern is when the OP asks an "XY problem" question, an answer points it out, and he changes the question to react to that.  Those answers now not only aren't answers but can look very tangential to people who don't review the edit history. Command prompt as SYSTEM user (Windows 7) How can I get a command prompt as the SYSTEM user on Windows&nbsp;7?  Context: I'm testing a computer startup script, and I need to figure out the behavior of a command when run as SYSTEM rather than my user account.  I've seen ways to do this with at and psexec, but those methods only appear to work on Windows&nbsp;XP or Windows&nbsp;Vista.  I'm using Windows&nbsp;7 Pro SP1. Add-on for blocking sites in Google Search I want to block Yahoo Answers from Google searches. As there is no option from Google for that, are there any extensions for Chrome or add-ons for Firefox that can block sub-domain results from Google search? Proving for all integer $n \ge 2$, $\sqrt n < \frac{1}{\sqrt 1} + \frac{1}{\sqrt 2}+\frac{1}{\sqrt 3}+\cdots+\frac{1}{\sqrt n}$ What are copy elision and return value optimization? I would like to replace the usual \hat in maths with a larger one, but I do not want it to stretch. The size I want is "the smallest \widehat" (as in $\widehat{.}$). Is there a way to put that one above a wide character like M ($\widehat{M}$ would stretch and give be an even wider hat).  I guess I have a lack of understanding for the mechanism behind accents that extend, so feel free to explain. Converting the beta coefficient from matrix to scalar notation in OLS regression "Unanswered" question sort order on profile pages To help users keep track of (and hopefully get answers to) unanswered questions, it would be useful to have an "unanswered" sort order on a user's profile page.  It would order the list of questions with unanswered questions first.   This would be in addition to the "recent," "views," "newest," and "votes" sort orders. SFDX Pull error: Entity of type 'ListView' named XXX cannot be found While trying to pull changes from a scratch org (sfdx force:source:pull, tried with and without -f), I'm getting this error:     Entity of type 'ListView' named 'Note_Relation__c.My_Notes' cannot be found.   I do have a custom object Note_Relation__c, and it exists both locally and in the scratch org.  However, it's not an object that is normally accessed directly.  It has no tab, and should have no list views.  Nonetheless, I've checked the object's list view (via prefix, e.g., /a0D in both Classic and LEX view), and I can find no list views at all.  I've also tried adding an entry to .forceignore:  force-app/main/default/objects/Note_Relation__c/listViews/My_Notes.listView   This has no effect either.  At this point, I'm stuck with a bunch of config changes in a scratch org that I cannot pull.  I can find no references to this error message with scratch orgs.  Has anyone seen this issue?  Edit to clarify: I tried the .forceignore line based on what I think the file name should be; I have no force-app/main/default/objects/Note_Relation__c/listViews directory locally.  Edit 2: Workaround:  I found a workaround that doesn't make sense to me, but it works.  I'm not adding it as an answer yet because I'm not sure what's happening.  The workaround is to add the following line to .forceignore  Note_Relation__c.My_Notes   Even though this isn't a DX filepath, it's the name from the error message, and it seems to work. Show that $n$ lines separate the plane into  $\frac{n^2+n+2}{2}$ regions if no two of these lines are parallel and no three pass through a common point.   I know we start with the base case, where, if we call the above equation P(n), P(0), for 0 lines would be 0.  But I really have no idea how to begin the inductive step.  How do we know what k+1 we're supposed to arrive at?  Thanks! My Ubuntu 14.04 is stuck when trying to login my desktop. The screen goes black and soon after that the login screen comes back.   I followed all steps in  but the issue was not solved. Bounded measurable function and integral with charcteristic function Why can't I connect to Ubuntu One? I have purchase new laptop from Dell with ubuntu 12.04 preinstalled. while connecting to Ubuntu One following occurs and I am not able to sync with Ubuntu One.   WebClientErr u'Error downloading https://one.ubuntu.com/api/account/ - server replied:Not       Found' u'&lt;!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"&gt;\n&lt;html&gt; &lt;head&gt;\n&lt;title&gt;404 Not Found&lt;/title&gt;\n&lt;/head&gt;&lt;body&gt;\n&lt;h1&gt; Not Found&lt;/h1&gt;\n&lt;p&gt;The requested URL /api/account/ was not found on this server. &lt;/p&gt;\n&lt;hr&gt;\n&lt;address&gt;Apache/2.2.22 (Ubuntu) Server at one.ubuntu.com Port 443 &lt;/address&gt;\n&lt;/body&gt;&lt;/html&gt;\n' If $$Y=\sum_{i=1}^{N}X_i^2$$ where $X_i \sim \mathcal{N}(0,\sigma^2)$, i.e. all $X_i$ are i.i.d. normal random variables of zero mean with same variances, then $$Y \sim \Gamma\left(\frac{N}{2},2\sigma^2\right).$$  I know the chi-squared distribution is a special case of the gamma distribution, but could not derive the chi-squared distribution for random variable $Y$. Any help, please? MacOS partition showing as "FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFF"