We suppose that I put my signature on a piece of white paper with my first and last name on it. After I execute a scan of this signature in .pdf, or .png or .tiff, etc. (as file image). What are the steps of a specific software to select only the signature, make the background transparent so that I can move it in a word document using only free tools on line without sign in or registration?
I need to upload my signature in a PDF document, but I do not know how to edit the background of this image.   I wish to remove the bluish-tint background, and make it pure white.   Can anyone help me with this, please?
Seeing through objects in Game engine Installing Cygwin packages from the command-line Alright, so the idea of an exponent, $x$, is that you are multiplying its base by itself $x$ number of times. With base $5$ and $x=3$, we have that $5^3$ = $5 \cdot 5 \cdot 5$  I understand that the logarithm with base $a$ of $x = c$,  tells us that  $$a^c = x$$  and for $c =$ positive; values for $x$ are greater than $1$, and for $c =$ negative; values for $x$ are less than $1$,  and for $c = 0$, values for $x$ are...$1$.  So in short, I understand how, by means of observation of the graph of $f(x) = \log x$, we can see that $f(1) = 0$, BUT, I see no other way to understand why $x^0 = 1$, apart from the graph and everything around that very point.  I honestly cannot get my head around the idea, "$5$ times itself $0$ times... is one".  Is it that there is no fundamental answer for this but that we simply know by the graph? Or can I truly understand $x^0 = 1$ on its own? Enable Careers and Jobs in app Please provide the Careers and Jobs features in the app. This will help us to closely interact with employers. It will be an additional advantage if you provide chat option with employers too.  We, as job seeker, would like to see ratings and feedback of previous employees too for that company, before making a decision of job change. Closures in a for loop How to prove $\cos\left(\pi\over7\right)-\cos\left({2\pi}\over7\right)+\cos\left({3\pi}\over7\right)=\cos\left({\pi}\over3 \right)$ Is there an easy way to prove the identity?     $$\cos \left ( \frac{\pi}{7} \right ) - \cos \left ( \frac{2\pi}{7} \right ) + \cos \left ( \frac{3\pi}{7} \right ) = \cos \left (\frac{\pi}{3} \right )$$   While solving one , I am stuck, which looks obvious but without any feasible way to approach.   Few observations, not sure if it would help $$ \begin{align} \dfrac{\dfrac{\pi}{7}+\dfrac{3\pi}{7}}{2} &amp;= \dfrac{2\pi}{7}\\\\ \dfrac{\pi}{7} + \dfrac{3\pi}{7} + \dfrac{2\pi}{7} &amp;= \pi - \dfrac{\pi}{7} \end{align} $$ "In" and "on": How can I decide which one to use for vehicles? Examples:   In a car, van, etc. On a bus, boat, motorcycle, etc.   How can one decide which preposition to use? Is memorization the only way or is there a better way?  Note: People generally explain this by either distinguishing between open and closed vehicles or between large and small vehicles. However, the examples I've given defeat both explanations. Intuition of the meaning of homology groups Integral ${\frac{1}{\pi^2}} \int_{0}^{\infty}\frac{{(\ln{x}})^2}{\sqrt{x}{(1-x)^2}} \mathrm d x$ The new Chip credit cards are being introduced to provide better security to consumers, merchants and credit card vendors.    Sample Card:   (source: )    Card Reader &amp; PIN Entry:    Are they really better from a security point of view?  What are the advantages and disadvantages? At the onset of my live usage in Ubuntu Gnome 15.10, use a bash script to set the colour of my gnome-terminal. The code used is link=/org/gnome/terminal/legacy/profiles:/:b1dcc9dd-5262-4d8d-a863-c897e6d979b9 dconf write $link/background-transparency-percent '10' dconf write $link/scrollback-unlimited true dconf write $link/use-theme-colors false dconf write $link/use-theme-transparency false dconf write $link/use-transparent-background true dconf write $link/foreground-color 'rgb(0,43,54)' dconf write $link/background-color 'rgb(131,148,150)'  The last 2 lines of the code give a key-value error. When I look at the dconf-editor org&gt;gnome&gt;terminal&gt;legacy&gt;profiles:&gt;{Default profile} the attributes  foreground-color background-color  are unavailable. How do I get rid of the error? Note: When done manually via gnome-ternimal&gt;Edit&gt;Profile Preferences&gt;Colours&gt;Built-in schemes the above attributes appear in the same location in dconf-editor. Fixed Field of $\sigma, \tau$ Let $k$ be a field and let $K=k(x)$ be the rational function field in one variable over $k$. Let $\DeclareMathOperator{\aut}{Aut}\sigma, \tau \in \aut(K)$ s.t. $$\sigma\left(\frac {f(x)}{ g(x)}\right)=\frac {f(1/x)}{g(1/x)}\qquad \&amp;\qquad \tau\left(\frac {f(x)}{ g(x)}\right)=\frac {f(1-x)}{g(1-x)}.$$ Find the fixed field $F$ of $&lt;\sigma, \tau&gt;$. Determine $\DeclareMathOperator{\gal}{Gal}\gal(k/F)$. Find an $h \in F$ so that $F=k(h)$.   Now for the first automorphism $\sigma$, I think if I concentrate on $k[x]$ it will give me some idea. Now, if $f(x)=a_0+a_1x+a_2x^2+ \cdots + a_nx^n \in k[x]$ then if $x^n \sigma(f(x))=f(x)$ the case will be $a_i=a_{n-i}$ $\forall i=0(1)[n/2]$. So all the funtions in $K$ which will be fixed by $\sigma$ are of the form $\frac {f(x)}{ g(x)}$ where $f(x)=a_0+a_1x+a_2x^2+ \cdots + a_nx^n$ and $g(x)=b_0+b_1x+b_2x^2+ \cdots + b_nx^n$ such that $a_i=a_{n-i}$ $\forall i=0(1)[n/2]$ and $b_i=b_{n-i}$ $\forall i=0(1)[n/2]$.   Please check whether am I right or not?  And any ideas for the rest of the part? Why use getters and setters/accessors? Why I can't edit "Your Communities" list in stackexchange.com and Area 51? I can edit &quot;YOUR COMMUNITIES&quot; in the upper left drop-down menu from any of my communities: (e.g. )    But in  portal there's no &quot;edit&quot; link:    Why is that and how can I edit the list in  portal? Is there a way to make IE8 honour opacity on an `:before` pseudo element? I just upgraded linux-firmware package and after that I used $ sudo update-initramfs -u -k all but I got some errors:  $ sudo update-initramfs -u -k all [sudo] password for piotrek:  update-initramfs: Generating /boot/initrd.img-4.4.0-34-generic Warning: No support for locale: en_US.utf8 update-initramfs: Generating /boot/initrd.img-4.4.0-31-generic Warning: No support for locale: en_US.utf8 update-initramfs: Generating /boot/initrd.img-4.4.0-13-generic WARNING: missing /lib/modules/4.4.0-13-generic Ensure all necessary drivers are built into the linux image! depmod: ERROR: could not open directory /lib/modules/4.4.0-13-generic: No such file or directory depmod: FATAL: could not search modules: No such file or directory Warning: No support for locale: en_US.utf8 depmod: WARNING: could not open /var/tmp/mkinitramfs_LJbkti/lib/modules/4.4.0-13-generic/modules.order: No such file or directory depmod: WARNING: could not open /var/tmp/mkinitramfs_LJbkti/lib/modules/4.4.0-13-generic/modules.builtin: No such file or directory   I'm sure I don't have kernel 4.4.0-13. I might have had it some time ago but removed it:   $ apt list --installed | grep linux-  WARNING: apt does not have a stable CLI interface. Use with caution in scripts.  linux-base/xenial,xenial,now 4.0ubuntu1 all [installed,automatic] linux-firmware/now 1.159 all [installed,local] linux-headers-4.4.0-31/xenial-updates,xenial-updates,xenial-security,xenial-security,now 4.4.0-31.50 all [installed] linux-headers-4.4.0-31-generic/xenial-updates,xenial-security,now 4.4.0-31.50 amd64 [installed] linux-headers-4.4.0-34/xenial-updates,xenial-updates,xenial-security,xenial-security,now 4.4.0-34.53 all [installed] linux-headers-4.4.0-34-generic/xenial-updates,xenial-security,now 4.4.0-34.53 amd64 [installed] linux-image-4.4.0-31-generic/xenial-updates,xenial-security,now 4.4.0-31.50 amd64 [installed] linux-image-4.4.0-34-generic/xenial-updates,xenial-security,now 4.4.0-34.53 amd64 [installed] linux-image-extra-4.4.0-31-generic/xenial-updates,xenial-security,now 4.4.0-31.50 amd64 [installed] linux-image-extra-4.4.0-34-generic/xenial-updates,xenial-security,now 4.4.0-34.53 amd64 [installed] linux-libc-dev/xenial-updates,xenial-security,now 4.4.0-34.53 amd64 [installed] linux-sound-base/xenial,xenial,now 1.0.25+dfsg-0ubuntu5 all [installed] syslinux-common/xenial,xenial,now 3:6.03+dfsg-11ubuntu1 all [installed] syslinux-legacy/xenial,now 2:3.63+dfsg-2ubuntu8 amd64 [installed]   How to fix those update-initramfs errors? In C#/VB.NET/.NET, which loop runs faster, for or foreach?  Ever since I read that a for loop works faster than a foreach loop a  I assumed it stood true for all collections, generic collections, all arrays, etc.  I scoured Google and found a few articles, but most of them are inconclusive (read comments on the articles) and open ended.  What would be ideal is to have each scenario listed and the best solution for the same.  For example (just an example of how it should be):   for iterating an array of 1000+ strings - for is better than foreach for iterating over IList (non generic) strings - foreach is better than for   A few references found on the web for the same:               [Edit]  Apart from the readability aspect of it, I am really interested in facts and figures. There are applications where the last mile of performance optimization squeezed do matter. How to change specific values in a List Finding the missing digits of $23!$ I'm not a git master, but I have been working with it for some time now, with several different projects.  In each project, I always git clone [repository] and from that point, can always git pull, so long as I don't have outstanding changes, of course.  Recently, I had to revert to a previous branch, and did so with git checkout 4f82a29.  When I was again ready to pull, I found that I had to set my branch back to master.  Now, I can not pull using a straight git pull but instead, have to specify git pull origin master, which is annoying, and indicates to me that I don't fully understand what is going on.  What has changed which does not allow me to do a straight git pull without specifying origin master, and how to I change it back?  UPDATE:  -bash-3.1$ cat config [core]     repositoryformatversion = 0     filemode = true     bare = false     logallrefupdates = true [branch "master"] [remote "origin"]     url = git@github.com:user/project.git     fetch = refs/heads/*:refs/remotes/origin/*   UPDATE 2: To be clear, I understand that my original method may have been incorrect, but I need to fix this repo so that I can simply use git pull again.  Currently, git pull results in:  -bash-3.1$ git pull You asked me to pull without telling me which branch you want to merge with, and 'branch.master.merge' in your configuration file does not tell me either.  Please name which branch you want to merge on the command line and try again (e.g. 'git pull  '). See git-pull(1) for details on the refspec.  If you often merge with the same branch, you may want to configure the following variables in your configuration file:      branch.master.remote =      branch.master.merge =      remote..url =      remote..fetch =   See git-config(1) for details.   I can tell git pull which branch to merge, and it works correctly, but git pull does not work as it did originally before my git checkout.