How to add an integer variable to a number in a .txt file in Python?
How to modify a text file?
What does the tilde before a function name mean in C#? How do I beat the Reaper on Rannoch? I'm having trouble with the last of the Rannoch missions, where Shep wakes up and takes on a Reaper.   Shepard has a targeting laser which will call in an orbital strike with the combined might of the Quarian Migrant Fleet, but there's two major problems standing between the commander and victory.   The Targeting Laser takes a while to power up. The Reaper is trying to kill you.   I can consistently avoid the Reaper's attacks for the first volley, but each time you hit it, the Reaper moves forwards, giving you less time to dodge future assaults. Is there some key to avoiding the Reaper's attacks? Strafing doesn't seem to be enough. How to rename the User folder in Windows 10? When is using the past perfect tense not necessary? When adding NOT NULL columns with a DEFAULT value - does PostgreSQL optimize this operation?  In case the table has n rows, a not-optimized alter-table-add-column would yield n writes of the default value - which could be very painful, obviously. With the optimization the DB would instantaneously create the new column, store just one copy of the default value which would be returned when no non-default value is found for that column in a suitable index data structure.  For example  such an . Let $q \in \mathbb C$, $|q|=1$ and $q^n \neq 1, \forall n \in \mathbb N$. Show that $\{q^n:  n \in \mathbb N\}$ is dense in $S^1$.  My attempt: As $(q^n)$ is limited, there is subsequence $(q^{n_j})$ convergent. So given $\epsilon &gt; 0, \exists j_0 \in \mathbb N, \quad |q^{n_j} - q^{n_k}| &lt; \epsilon, \quad \forall j,k \geq j_0$. Supose that $n_j &gt; n_k$, then  $|q^{n_j} - q^{n_k}| = |q^{n_k}||q^{n_j - n_k} - 1| = |q^{n_j - n_k} - 1| &lt; \epsilon, \quad \forall j, k \geq j_0$. So, there is a subsequence of $(q^n)$ that converges to $1$.  Using this fact, how can I ensure that for all $w \in S^1$ there is a subsequence of $(q^n)$ that converges to  $w$? Routing sound from different cards to a single output I have a setup where I am monitoring for silence on an incoming stream on 3 different audio cards.  When I detect silence on the master I switch to the secondary, and if I detect silence there I switch to the last card.  The way I have it set up I load/unload the loopback module for each card depending on who's the active card.  This has the inconvenience that I need a 3-to-1 minijack cable to be able to maintain the stream.  Can I load the loopback module and point the output to a single card (independently of the input card)?  How can I route the audio from any input to a single output? How to determine the class of a generic type? Cyclic vectors in a real vector space Let $V$ be an n-dimensional vector space over $\mathbb{R}$ and $T:V \rightarrow V$ be linear. Call a vector $v \in V$ cyclic if $V$ is spanned by $\{v, \ Tv, \ T^2v,..\}$.  Question:  Show that $v$ is cyclic for $T$ then there is some $k \geq 1$ such that   $$B=\{v, \ Tv,..T^{k-1}v \}$$ is linearly independent in $V$ and that $T^kv$ lies in  the span of $B$.  Thoughts:  If we suppose that no such $k$ exists, then every subset of the form $\{v, \ Tv,..T^{l-1}v \}$ is linearly dependent, or it is linearly dependent with $T^lv$ not lying in it span.  There are in effect then two cases to consider.  Suppose every subset of the form $\{v, \ Tv,..T^{l-1}v \}$ is linearly dependent. Then $T^{l-1}$ can be expressed as a linear combination of $v,...,T^{l-2}v$. Now, $\{v, \ Tv,..T^{l-2}v \}$ is also linearly dependent by assumption and so we can express $T^{l-2}$ as a linear combination of  $v,...,T^{l-3}v$ etc... Continuing in this way, we show that $T^{l-1}v= \lambda v$ for some $\lambda \in \mathbb{R}$. Thus $$B=\{ \mu v \ | \ \mu \ \text{is an eigenvalue of} \ T^mv \ \text{for some} \ m \}$$ This is 'at best' countably infinite, and therefore could not span $V$ even if it were 1-dimensional, wince our base field is $\mathbb{R}$, which is uncountable.  Suppose then that $B$ is linearly independent for some $k$ but that $T^kv$ does not lie in its span. I can't see how to progress this argument.  Note: This question is for second year Undergraduates, and I think there must be some more simple approach; even the first part surprises me if we need to argue using the uncountability of $\mathbb{R}$, so any alternative approaches are also appreciated. Electrolytic Capacitor Voltage Rating vs capacitance I have always believed that it was ok to replace a capacitor with a slightly higher voltage rated one. eg 16v with 25v.Going higher than this would risk the capacitance value being out at the working voltage. However I just read the following quote from this       Electrolytic capacitors are non-ferroelectric with a very low dielectric constant. Their capacitance is derived from a very high surface area and nanometer thick dielectric layers. Their capacitance is not a function of applied voltage.‐Design Solutions For DC Bias In Multilayer Ceramic Capacitors (August 2010 Electronic Engineering Times)   So does this rule not apply to aluminum electrolytics? Eg will I have no issues replacing an electrolytic 25v 100uf with a 50v 100uf assuming both are low esr, similar footprint and good quailty? How do I get rid of the noise on my Hayes Stroker Trail brakes I have 12.10 ubuntu and when I try to remove / install programs I get notification :      Software can't be installed or removed because the authentication service is not available.    (org.freedesktop.PolicyKit.Error.Failed: ('system-bus-name', {'name':  ':1.104'}): org.debian.apt.install-or-remove-packages   When I log in as root user (instead of user account that I regulary use) i have no problems. Small caps font warning in beamer using biblatex Consider the following MWE  \documentclass{beamer} \usepackage{silence} \WarningFilter{biblatex}{Patching footnotes failed}  \usepackage{lmodern} \usepackage[T1]{fontenc}  \usepackage[style=authoryear-comp,backend=biber]{biblatex} \addbibresource{biblatex-examples.bib}  \begin{document} \begin{frame}   \fullcite{sarfraz} \end{frame} \end{document}   This generates the warning:  LaTeX Font Warning: Font shape `T1/lmss/m/sc' in size &lt;10.95&gt; not available (Font)              Font shape `T1/lmr/m/sc' tried instead on input line 28.   Is there a way to avoid the warning without using the silence package? Undergraduate/High-School-Olympiad Level Introductory Number Theory Books For Self-Learning How to use if-else option in JSTL Giving a single user write permissions I want to grant a single user write permissions to a directory owned by root over command line. With chmod, it seems that I can only change the permissions for owner, group and other, not for a specific user. Ubuntu 17.10 Keyboard not working after login following upgrade from 17.04 (Gnome version) I have a very simple question. When I do this:  \catcode`\@=0 \catcode`\\=11 @mycommand{a} @catcode`@\=0 \catcode`\@=11   It works perfectly and calls \mycommand correctly. However, when I try to define \mycommand with similar trickery:  \newcommand\mycommand[1]{   \catcode`\@=0   \catcode`\\=11   @textbf{Hello #1}   @catcode`@\=0   \catcode`\@=11 }   compilation stalls and gives me the * prompt. If I give it Ctrl+D, it terminates without producing any output. Indeed, it seems that changing the catcodes inside a command has no effect whatsoever, because the following works perfectly (whereas, from my understanding, it shouldn't):  \newcommand\mycommand[1]{   \catcode`\@=0   \catcode`\\=11   \textbf{Hello #1} }   Can anybody please explain to me what's happening? What Happens to electrons after Alpha Decay and Nuclear Fission? In the sentence     What’s funny is Cat’s dry humour.   Wouldn’t it be better to put a comma after “funny”:     What’s funny, is Cat’s dry humour.   This question entails a (at the time of writing) heated discussion in the .