Rename user account on Windows 7 Home
How do I change a user name in Windows 7?
I am having a lot of trouble with these series questions. Up until this point, I had relatively little trouble with all the questions in the book. These seem to require knowledge about approximations of functions and other external experience-based knowledge, which I just don't have yet.  Determine convergence or divergence of the given series. In the case of convergence, determine whether the series converges absolutely or conditionally.  $$\sum_{n=1}^\infty (-1)^n\left[e-\left(1+\frac 1 n \right)^n\right]$$  It's easy to see that  $$\lim_{n\to\infty}\left[e-\left(1+\frac 1 n\right)^n\right]=0$$  however, in order to apply Leibniz's Rule and show conditional convergence I need to show that the sequence is monotonically decreasing. This doesn't seem doable with straight inequalities, so I tried taking the derivative, which just resulted in an uninterpretable mess. This doesn't even begin to address the question of absolute convergence/divergence.  There are 54 of these questions... I must be missing something really fundamental if they all take this long. Is it always better to use the whole dataset to train the final model? A common technique after training, validating and testing the Machine Learning model of preference is to use the complete dataset, including the testing subset, to train a final model to deploy it on, e.g. a product.      My question is: Is it always for the best to do so? What if the   performance actually deteriorates?   For example, let us assume a case where the model scores around 65% in classifying the testing subset. This could mean that either the model is trained insufficiently OR that the testing subset consists of outliers. In the latter case, training the final model with them would decrease its performance and you find out only after deploying it.   Re-phrasing my initial question:     If you had a one-time demonstration of a model, such as deploying it   on embedded electronics on-board an expensive rocket experiment, would you trust a   model that has been re-trained with the test subset in the final step without being   re-tested on its new performance? Calculate relative time in C# Given a specific DateTime value, how do I display relative time, like:   2 hours ago 3 days ago a month ago Probability of Obtaining the Roots in a Quadratic Equation by Throwing a Die Three Times relation between $R^2$ of simple regression and multiple regression A very basic question concerning the $R^2$ of OLS regressions   run OLS regression y ~ x1, we have an $R^2$, say 0.3 run OLS regression y ~ x2, we have another $R^2$, say 0.4 now we run a regression y ~ x1 + x2, what value can this regression's R squared be?   I think it's clear the $R^2$ for the multiple regression should be no less than 0.4, but is it possible for it to be more than 0.7? Why does Linux show both more and less memory than I physically have installed? Different methods to compute $\sum\limits_{k=1}^\infty \frac{1}{k^2}$ (Basel problem) As I have heard people did not trust Euler when he first discovered the formula (solution of the ) $$\zeta(2)=\sum_{k=1}^\infty \frac{1}{k^2}=\frac{\pi^2}{6}.$$ However, Euler was Euler and he gave other proofs.   I believe many of you know some nice proofs of this, can you please share it with us? After I read that companions don't drain the fusion core of a Power Armor when wearing it, I decided to try giving my armor to Nick so I'll always have it close by if I need it.  But I was wondering if there are any other drawbacks to that. For example, does the Armor get damaged or destroyed when the companion is under fire? Book where girl can grow nails and might be a thief I'll apologize for this being a vague description up front. I read a book about 8 years ago about a girl who could grow her nails into essentially razorblades or long enough that they could be used as razors. She travels to a city and either becomes an assassin or a thief (pretty sure it was a thief). I vaguely remember the book opening with her being chased by a mob. At some point during her thief training she realizes that the layout of the city is the key to some important plot device. I think she was given some scroll or cryptic image and then during her training she realizes that the layout of the city correlates to it.  Although I did read this 8 years ago I'm pretty sure the book was at least 5-10 years older than that, maybe even more because it was my mom who gave it to me and she said had read it when she was younger. The dust cover was missing when I read it so I have no description for the cover. I do remember that the author was male. It was a fantasy setting and there may have been vampires involved at some point but that part of my recollection of the book is even fuzzier than what I've already described. I've tried googling for this book but obviously my description is fairly vague. I will gladly answer any follow up questions that I can to try and help figure this out because it has been bothering me for years. I'm wondering about the period character . used as a shortcut for the local computer name.  You can use it when logging into Windows 7, for example, to specify that the user account you're entering belongs to the local computer rather than to a domain:  .\MyLocalUserAccount   And you can use it within a Windows Management Instrumentation (WMI) query to indicate that the target is the local computer rather than a remote computer.  You can also use it when working with named pipes to for similar purposes.  However, you cannot use it as the UNC network name for the computer, like this:  \\.\MyShare   Does this character have an official name (e.g. "LocalHostToken") and when and where can it be used for this purpose? How does HOTP keep in sync? creating a csv file from two csv files I have two csv files:  sub_compiler.to_csv('sub_compiler.csv') sub_compiler.head()     and   sub_opt = pd.read_csv('sub_opt.csv') sub_opt.head()     and what I would like to do is to create a csv file where I have something of the form   compiler, opt   How could I do this? I need to do this to make a submission.  Thank's in advance.  [EDIT] Thank you for the answers. Now I have obtained :    don't understand why I have the columns called unnamed.   My objective is to get a csv file that contains only the columns compiler and opt. How could I do this? Thank's again.  [EDIT 2] I have solved my problem but if I open the csv file manually, so just click on the file, I have the following:    s it contains only 11 lines, but it contains 3000 lines in jupyter. Is it there something wrong?  [EDIT 3] I tried to to the following:  import pandas as pd  test = pd.read_csv('1495927.csv') test   and I have:    where 1495927.csv is the csv file I have created and that is in the image where I have 11 elements. Does math have an incorrect notation / syntax? I don't mean writing misaligned notation (google), but when you take something like a number to powers to powers to powers, $${{2^2}^2}^3$$ (I was told this is incorrect notation by a teacher). Is it really incorrect, or does it just need to be simplified with parentheses? Do people write maths like this?  a radical expression with the root being a radical expression? $$\sqrt[\sqrt{2^3}]{2}$$ I just installed Dufour on my Windows 7 Lenovo ThinkCentre desktop. When I open 2.0.1 I get this error window:    And when I try to add the 'Add Delimited Text Layer' plugin I get this message:    When I click 'OK' the program closes.   Any help is greatly appreciated - thanks. Efficient computation of $\sum_{k=1}^n \left\lfloor \frac{n}{k}\right\rfloor$ I realize that there is probably not a closed form, but is there an efficient way to calculate the following expression?  $$\sum_{k=1}^n \left\lfloor \frac{n}{k}\right\rfloor$$  I've noticed $$\sum_{k=1}^n \left\lfloor \frac{n}{k}\right\rfloor = \left\lfloor\frac{1}{2}\sum_{k=1}^{\left\lfloor\frac{n}{2}\right\rfloor} \left\lfloor\frac{n}{k}\right\rfloor\right\rfloor + \sum_{k=1,\ odd(k)}^n \left\lfloor \frac{n}{k}\right\rfloor$$  But I can't see an easy way to let the second term enter in a recursion. How to show that the commutator subgroup is a normal subgroup It is suggested as an exercise in Serge Lang's book "Algebra" to show that the commutator subgroup $G^c$ of a group $G$ is a normal subgroup.   I'd like to do that but I am afraid I need help,   I think the first thing I need to figure out is how a general element in the commutator subgroup looks like, so that I can check that the defining condition for normality is satisfied.  That is, supposing for a moment that a general element in $G^c$ is denoted by $g$, I need to show that $aga^{-1} \in G^c,$ for all $a \in G$.  But here I get stuck, first because I am unsure how to write a general element in $G^c$ - a simple product in $G^c$ is of the form $xyx^{-1}y^{-1}aba^{-1}b^{-1}$ where $a,b \in G$. I cannot see a way to simplify this - I am sure there is one, but somehow I am blind today.  The second thing then is, even if one tries out the conjugation of a simple element like $xyx^{-1}y^{-1}$ in $G^c$, again not simplification offers itself easily I think .. what am I missing ?  An alternative would be to find a homomorphism of $G$ whose kernel is precisely $G^c$ - here I tried to think of this as a map $G \times G \to G$ but whatever I cook up is not a homomorphism.  Thanks for your hints !! Remotely changing hard drive boot order, windows 7 Do companies have IT "spyware" on corporate iPhones? How to detect end of line with sed I'm looking for a way to only execute replacement when the last character is a newline, using sed.  For instance:  lettersAtEndOfLine   is replaced, but this is not:  lettersWithCharacterAfter&amp;   Since sed does not work well with newlines, it is not as simple as  $ sed -E "s/[a-zA-Z]*\n/replace/" file.txt   How can this be accomplished? .NET Process.Start default directory? I'm firing off a Java application from inside of a C#  console application. It works fine for the case where the Java application doesn't care what the "default" directory is, but fails for a Java application that only searches the current directory for support files.  Is there a process parameter that can be set to specify the default directory that a process is started in?