For an assignment, I was asked to make a simple addition calculator in Python using a loop, so I made a program that usually works, but when I add some floats, the total is off just by a little. Here is my program:  number = 0 total = float(input('Enter positive numbers you want to add, or enter a\ \nnegative number to calculate the sum:\n\t')) while number &gt;= 0:     total += number     number = float(input('+\t')) if number &lt; 0:     print('=\t', format(total, ','), sep='')   An example of an incorrect output is when 0.1+0.2+0.3 is input, the output is 0.6000000000000001. Does anyone know what's causing this very small difference?
Consider the following code:   0.1 + 0.2 == 0.3  -&gt;  false   0.1 + 0.2         -&gt;  0.30000000000000004   Why do these inaccuracies happen?
How can I String.Format a TimeSpan object with a custom format in .NET? How would you explain JavaScript closures to someone with a knowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?  I have seen  given on Wikipedia, but unfortunately it did not help. Show that if $\lim_{x\to a}f'(x) = A$ then $f'(a)$ exists and equals A I ran across this problem in my Analysis class and can't seem to come up with a good solution. Here's the question: Show that if $\lim_{x\to a}f'(x) = A$ then $f'(a)$ exists and equals $A$. $f$ is continuous on $[a,b]$ and differentiable on $(a,b)$.  I tried applying the Mean Value theorem like this: There exists a $c \in (a, x)$ st $f(x)-f(a)=f'(c)(x-a) \implies \frac{f(x)-f(a)}{x-a}=f'(c) \implies f'(a)=\lim_{x\to a}\frac{f(x)-f(a)}{x-a}=\lim_{c\to a}f'(c)=A$  However, I think this is wrong. I am pretty sure the Mean Value theorem is needed, but my application of it seems to be incorrect. Would somebody be able to point me in the right direction? Any site that I visit can see my local IP (e.g. 192.168.1.102). Is there any reliable way to block this behavior? (browser setting, OS setting, router setting, etc.) I am particularity interested in Google Chrome and Mozilla Firefox, but any modern open source browser will do. If it is a browser plugin, it should be open source with a solid user base.  By reliable I mean, that I do not need to check the leakage again after every software update.  More info / what I have read so far:   There was a Chrome plugin that is not working anymore Local IP is obtained using JavaScript / WebRTC   Live Demo here:  Source code:   Firefox developers is not going to fix the leak (bug is open from 2014):  In Private / Incognito mode does not prevent this leak. If you use static IPs, and have non typical local IP (e.g. 10.66.77.88 or 192.168.212.121), then there is no need for . Your external IP + internal IP is perfect fingerprint.   Update 1: It is not duplicate of  - I want to prevent private / local IP leak, not disable all WebRTC.  Update 2: No, it is not related to header X-Forwarded-For (HTTP_X_FORWARDED_FOR), that is added when user/administrator chooses to do so. In my provided demo it is not your choice... It is Google's and Mozilla's choice to leak your private IP even when using private browsing mode.  Update 3: Ability to determine my local IP allows malicious JavaScript to quickly identify my local subnet and print on my local network printers from any website in the world without me doing anything.  This  finds my LAN printers using JavaScript.  Update 4: It is not a good idea to reveal private IP to every website. By seeing your private IP, for example 192.168.88.101, I can guess with very high probability that you are using MikroTik router. Also, I can track particular user event if user uses different browsers because local and remote IP stays the same for some time (hours or even days). I'm running Windows 7. It seems that svchost is eating up a lot of memory.   The user name for the particular svchost instance is "Network Service". The description is "Host Process for Windows Services".   Sometimes it eats up 50% of the CPU usage. Other times, it's just under 5%. I can't figure out when it's 50% and when it's not. But it fluctuates often -- even when I've just booted up and no programs were started.  How do I diagnose this? Following my question , I am wondering if there are strong views for or against the use of standard deviation to detect outliers (e.g. any datapoint that is more than 2 standard deviation is an outlier).  I know this is dependent on the context of the study, for instance a data point, 48kg, will certainly be an outlier in a study of babies' weight but not in a study of adults' weight.  Outliers are the result of a number of factors such as data entry mistakes. In my case, these processes are robust.   I guess the question I am asking is: Is using standard deviation a sound method for detecting outliers? Could I have a hint for testing the convergence of the following series please?  $$\sum_{n=2}^\infty\frac{1}{(\ln n)^{\ln n}}$$  I am very appreciative for your help. Can I, as a reviewer, tell authors to get a native English speaker to proofread their paper? I am reviewing a paper for possible publication in a respected journal. The English in the paper is very poor. The authors are clearly not native English speakers. I want to write something to the effect of the following in my review.   I advise the authors to find a native English speaker to proofread the manuscript.    My question: Is this appropriate in a review?  On one hand, I think it is good, constructive advice. The paper would be significantly clearer if someone spent a few hours helping them fix it up. I can try to help them through reviewer comments, but it would be much easier if someone could help them in person. The authors are located in a western English-speaking country, so they should be able to find someone.  On the other hand, I don't want to be "the mean reviewer." I understand that English can be difficult to master for immigrants. Perhaps there is a more diplomatic way of saying this. Why are image thumbnails cropped proportionally (not per dimensions)? For some reason WordPress is ignoring my thumbnail sizes and keeping thumbnails cropped proportionately instead of specific dimensions. Here is what I have in functions.php:  add_image_size( 'main-thumbnail', 728, 410, true );   and in content.php:  &lt;div class="thumbnail"&gt;     &lt;a href="&lt;?php the_permalink(); ?&gt;"&gt;        &lt;?php the_post_thumbnail( 'main-thumbnail' ); ?&gt;     &lt;/a&gt; &lt;/div&gt;   I added these two things and regenerated my images with the  plugin, but it doesn't seem to matter. The images don't change.  For some reason WordPress isn't recognizing the hard crop and is keeping the images proportional, so some of my images are way taller than 410 pixels. Why is this? Number theory in Physics As a Graduate Mathematics student, my interest lies in Number theory. I am curious to know if Number theory has any connections or applications to physics. I have never even heard of any applications of Number theory to physics. I have heard Applications of linear algebra and analysis to many branches of physics, but not number theory.  Waiting forward in receiving interesting answers! I'm writing my thesis using MiKTeX and WinEdt 9 for Windows. I write the different chapters individually, and then I have a "masterfille" with the documentclass "report" where I use the command "input" to load the individual chapters. In other words there is only a preamble in the "masterfile".  I have a very general problem which is the following: No matter what kind of mistake I do whatsoever, I will first receive the correct error message, say I forgot to end a table or something (it really does not matter). If I correct this mistake and try to recompile without using the option "Erase Output Files" in Winedt, I will always and very quickly receive a new error message, often containing a mysterious "Undefined control sequence". Having to do this every time and to recompile plus run the Biber (L+B+L+L+D) is very time consuming, since the document is very large. Any ideas what the problem could be? Here is the preamble of my "masterfile" (I am probably including irrelevant information, sorry for that):   \documentclass[12]{report} \setcounter{tocdepth}{2} \usepackage{layout} \setlength{\voffset}{-0.75in} \setlength{\headsep}{5pt} \usepackage[utf8]{inputenc} \usepackage[english]{babel} \usepackage{csquotes} \usepackage{authblk} \usepackage [T1]{fontenc} \usepackage[backend=biber, style=authoryear-comp]{biblatex} \usepackage{xyling} \usepackage[super]{nth} \usepackage{xspace} \usepackage{cgloss4e} \usepackage{abstract} \usepackage{array} \usepackage{multirow} \usepackage{hyperref} \usepackage{xr} \usepackage{gb4e} \noautomath  \let\eachwordone\itshape   \makeatletter \pretocmd{\@footnotetext}{     \@noftnotefalse\setcounter{fnx}{0}%     \renewcommand{\thexnumi}{\roman{xnumi}}     }{}{} \apptocmd{\@footnotetext}{     \@noftnotetrue     \renewcommand{\thexnumi}{\arabic{xnumi}}     }{}{} \@ifpackageloaded{bidi}{% \pretocmd{\@LTRfootnotetext}{     \@noftnotefalse\setcounter{fnx}{0}%     \renewcommand{\thexnumi}{\roman{xnumi}}     }{}{} \apptocmd{\@LTRfootnotetext}{     \@noftnotetrue     \renewcommand{\thexnumi}{\arabic{xnumi}}     }{}{} } \makeatother     \addbibresource{ref.bib}    \title{The origins of Old Romance V2: A comparative study of Late Latin, Old French and Middle High German} \author{XXX} \date{\today}   \begin{document}  \tableofcontents   \chapter{Old French} \input{chapters/OldFrench2}  \printbibliography  \end{document} Sugar as a defence against bacteria? mentions that sugar "at a certain level acts as a preservative". I've always been taught that microorganisms eat sugar and expel acids, that is why sugary food are damaging to teeth. How is it that sugar acts as a preservative, then?  Googling the question I've found   though I don't credit the sources as being especially reputable. What is the real reason that sugar can act as a preservative? What are the pros and cons of adding a vapor barrier behind shower backer board? Why would the First Order have lightsaber-resistant batons? In The Force Awakens there is a new Stormtroopr who is equipped with a lightsaber-resistant baton.    Except for one thing:   In Revenge of the Sith, most of the Jedi are killed. During the original Star Wars trilogy the last few remaining Jedi — except for Luke Skywalker — die.     And before The Force Awakens Kylo Ren kills off everyone at Luke’s school and drives Luke into exile.    There are practically no lightsabers in existence, so why are these weapons deployed at all if their only use is in counter-lightsaber combat? Why use gradient descent with neural networks? When training a neural network using the back-propagation algorithm, the gradient descent method is used to determine the weight updates. My question is: Rather than using gradient descent method to slowly locate the minimum point with respect to a certain weight, why don't we just set the derivative $\frac{d(\text{Error})}{dw}=0$, and find the value of weight $w$ which minimizes the error? Also, why are we sure that the error function in back-propagation will be a minimum? Can't it turn out the error function is a maximum instead? Is there a specific property of the squashing functions that guarantees that a network with any number of hidden nodes with arbitrary weights and input vectors will always give an error function that has some minima? CPU governor changes automatically to "performance" under load I have a Lenovo T570 with Xubuntu 18.04 LTS. My current issue is that my cpu speed stepping is kind of going nuts and does what ever it thinks its best.  Sample: when I run my IDE and cpu load increases during build time, the governor changes automatically. I caught the moment during compiling my project with the following call:  martin@martin-ThinkPad-T570:~$ while cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor; do sleep 1; done powersave powersave performance performance   cpufreq-info tells me this:  martin@martin-ThinkPad-T570:~$ cpufreq-info  cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009 Report errors and bugs to cpufreq@vger.kernel.org, please. analyzing CPU 0:   driver: intel_pstate   CPUs which run at the same hardware frequency: 0   CPUs which need to have their frequency coordinated by software: 0   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.25 GHz. analyzing CPU 1:   driver: intel_pstate   CPUs which run at the same hardware frequency: 1   CPUs which need to have their frequency coordinated by software: 1   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.36 GHz. analyzing CPU 2:   driver: intel_pstate   CPUs which run at the same hardware frequency: 2   CPUs which need to have their frequency coordinated by software: 2   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.26 GHz. analyzing CPU 3:   driver: intel_pstate   CPUs which run at the same hardware frequency: 3   CPUs which need to have their frequency coordinated by software: 3   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.36 GHz.   Please take a look at     current policy: frequency should be within 3.50 GHz and 3.50 GHz.       The governor "performance" may decide which speed to use   Afterwards to go back to powersave I use my little script:  martin@martin-ThinkPad-T570:~$ cat cpu_freq_save.sh  #!/bin/bash sudo cpufreq-set -g powersave -c 0 --min 400MHz sudo cpufreq-set -g powersave -c 1 --min 400MHz sudo cpufreq-set -g powersave -c 2 --min 400MHz sudo cpufreq-set -g powersave -c 3 --min 400MHz   Which resets the min frequency and the governor but as soon as I compile again with my IDE every time the governor and the min frequency changes again.  Any idea how I can disable that automatic change?  PS: If you need more details, just tell me where to find them and I will provide them Would the Animate Objects spell end an ongoing spell affecting the targeted object(s)? On my Amazing 2GB EeePC Surf, I have no more space left!  This is quite normal, and it happens every now and then. Just delete a few large, unneeded files and everything should be good, right?  So I go and find a 2MB file in /tmp, and rm -rf it. Check free space again, and -- still nothing?!  I had to remove about 30MB of files before it registered some free space.  Now, my question is, what's up with this strange behaviour? Randomly selecting elements without repetition \@seccntformat only for section