I accidentally deleted the .profile in my Ubuntu 18.04 today. How to retrieve this.  regards,
Several files in my home directory have been disappearing. E.g. .bashrc, .bash_profile, authorized_keys and now .profile.  Regardless of how this happened, I would like to restore the original pristine .profile file. If I create a new user on my system one is created. Where can I find this .profile contents from a fresh, untouched install?
Calculate limiting distribution of $\frac{\sum_{i=1}^n X_i}{\sum_{i=1}^n Y_i}$ I don't have cd burner, so I want to install W7 on my 2nd computer via an USB-Drive. I just copied the files from the iso but it won't boot. So I installed ms-sys and did a ms-sys -7 /dev/sdb but it just says "Boot error".  How can I install it the right way? Tried many different tutorials by now but none worked. Suppose k is an integer such that $6k + 1$, $12k + 1$, $18k + 1$ are primes. Show that $n = (6k + 1)(12k + 1)(18k + 1)$ is a Carmichael number. Suppose k is an integer such that $6k + 1$, $12k + 1$, $18k + 1$ are primes. Show that $n = (6k + 1)(12k + 1)(18k + 1)$ is a Carmichael number.  This is a question on a past exam that I find difficulty to answer. Can anyone help? Check the uniform convergence of series of functions Check that given series converges uniformly for $x\in(-\pi,\pi)$ or not  1) $\sum_{n=1}^{\infty} (\frac{x}{n})^n$  2) $\sum_{n=1}^{\infty}\frac{1}{((x+\pi)n)^2}$  first series is power series so I find the radius of convergence that comes $R=e$ which is inside the given set so I am not able to give the final conclusion. after this I were thinking to apply $M_n$ test , but I am not able to find $M_n$. Please help to solve this problem. MySQL search in comma list Making tags visible when using a Tumblr theme that doesn't show them Time reversal symmetry and T^2 = -1 The more I use Stack Exchange, the more it is getting a knowledge-base for me. All questions, that I need for later reference I mark as favorite. Now I need to store these pages locally on my laptop. It is really time-consuming:  I could use Ctrl+S on each favorite question page  on Linux: there could be a solution with wget -N -r -l 1 &quot;https://stackoverflow.com/users/1069083/rubo77?tab=favorites&quot;  this will download all favorite questions but it creates no correct index.html Another approach would be to use the  to automatically follow into all your Stack Exchange-accounts. But that would have to be somehow limited to only favorites links on your  in each stack. cross-platform: You would need a firefox-plugin that downloads links recursively but only within the favorite-area of the  in your stack  Additionally, I would like to  and Ridiculous error on all google play store Using CM 10.1.3 I have very old Computer  What's the Best Operating System for Old Computer? Is there any way to add pasta to soup without the pasta doubling in size and getting mushy in the fridge later.I've even tried putting uncooked pasta in with the same result. Multiplicative inverse questions This is my first time posting on Math exchange. I have been self-teaching myself Mathematics and recently started learning some Algebra. I was posed the following questions, in which I would like to answer before I proceed, but having some trouble finding proper solutions. So the format will be question, and my answer.      What name do we give an element $a \in \mathbb{Z}_n$ that has a multiplicative inverse?   A modular multiplicative inverse of an integer $a$ is an integer $x$ such that $ax \cong 1 (\mod m)$. This means that the remainder after dividing $ax$ by integer $m$ is equal to $1$.      Give an example, for some $n \in \mathbb{N}$, of an element of $\mathbb{Z}_n$, that does not have a multiplicative inverse?   This question is throwing me off because - does the $n$ we speak of matter for both $n \in \mathbb{N}$ and $\mathbb{Z}_n$ ot solely $n$? My guess here would be $0$ because we cannot have an inverse of $0$.      Prove that multiplicative inverse are unique; an element $a \in \mathbb{Z}_n$ cannot have two multiplicative inverses.    Suppose that an element $a\in\mathbb{Z}_n$ has an inverse $a'$. Next, suppose that $a^*$ is also an inverse of $a$. Then, $a'$ is a solution to $a \cdot_n x=1$, and similarly $a^*$ has a solution to $a \cdot_n x=1$.   Lemma: Suppose $a'$ is multiplicative inverse of $a$ in $\mathbb{Z}_n$, then for any $b \in \mathbb{Z}_n$ the equation $a \cdot_n x=b$ has a unique solution, such that $x = a' \cdot_n b$.   By Lemma, equation $a \cdot_n x = 1$ has a unique solution, namely $x=a'=a^*$. Therefore, an element $a\in \mathbb{Z}_n$ cannot have two multiplicative inverses.    Thank you for the help. I would love any constructive feedback for these. If you can help me elaborate on some ideas, that would be really helpful also.  Thank you very much! I'm reading Galois Theory by Steven H. Weintraub (second edition), and finding that I'm at least somewhat short on the prerequisites. However the following proof looks wrong to me - am I misunderstanding something, or is it actually an incorrect proof?  Lemma 2.2.3. Let $F$ be a field and $R$ an integral domain that is a finite-dimensional $F$-vector space. Then $R$ is a field. Proof. We need to show that any nonzero $r \in R$ has an inverse. Consider $\{1, r, r^2, \cdots\}$. This is an infinite set of elements of $R$, and by hypothesis $R$ is finite dimensional as an $F$-vector space, so this set is linearly dependent. Hence $\sum_{i=0}^n{c_i r^i} = 0$ for some $n$ and some $c_i \in F$ not all zero.  It then goes on to show, given the above, that we can derive an inverse for $r$. However, if I consider examples like $r = 2 \in Q[\sqrt{2}]$, $r = \sqrt{2} \in Q[\sqrt{2}]$ or $r = 2 \in Q[X]/{&lt;X^2&gt;}$, the set $\{1, r, r^2, ...\}$ doesn't look linearly dependent to me. I do believe the lemma is true (and might even be able to prove it), but this does not look like a correct proof to me. Am I missing something? [Edit] Well yes, I am. Somehow I had managed to discount the possibility of any $c_i$ being negative, despite repeatedly looking at each fragment of the quoted text in an attempt to find what I might be misunderstanding. Types of photon qubit encoding How many types of qubit encoding on photons exist nowadays? I know only two:   Encoding on polarization: $$ \lvert \Psi \rangle = \alpha \lvert H \rangle + \beta \lvert V \rangle $$ $$ \lvert H \rangle = \int_{-\infty}^{\infty} d\mathbf{k}\ f(\mathbf{k}) e^{-iw_k t} \hat{a}^\dagger_{H}(\mathbf{k}) \lvert 0 \rangle_\text{Vacuum} $$ $$ \lvert V \rangle = \int_{-\infty}^{\infty} d\mathbf{k}\ f(\mathbf{k}) e^{-iw_k t} \hat{a}^\dagger_{V}(\mathbf{k}) \lvert 0 \rangle_\text{Vacuum} $$ Time-bin: $$ \lvert \Psi \rangle = \alpha \lvert 0 \rangle + \beta \lvert 1 \rangle $$ $$ \lvert 0 \rangle = \int_{-\infty}^{\infty} dz\ f\left(\frac{t -z/c}{\delta t_{ph}}\right) e^{-i w_0 (t-z/c)} \hat{a}^\dagger(z) \lvert 0 \rangle_\text{Vacuum} $$ $$ \lvert 1 \rangle = \int_{-\infty}^{\infty} dz\ f\left(\frac{t -z/c+\tau}{\delta t_{ph}}\right) e^{-i w_0 (t-z/c+\tau)} \hat{a}^\dagger(z) \lvert 0 \rangle_\text{Vacuum} $$   Is there anything else? Schadenfreude is the joy or pleasure derived from the misfortunes of others. What is the word for joy or pleasure derived from the happiness of others? I need to find the caller of a method. Is it possible using stacktrace or reflection? What is the relationship between philosophy and science? While philosophy and science as held as separate disciplines (and often taught in completely different colleges within a university [i.e. College of Liberal Arts vs. College of Science]), it is patently clear that there is an immutable relationship between philosophy and science. Philosophy can often be seen as providing justification for particular scientific theories -- but why/how is this so?  In science:   A theory must have observable consequences that can be tested and be falsified.   Theories also must agree with previous theories in the domains where they had been successfully tested.   For example,  special relativity reduces to Newton mechanics in the domain of velocities much less than the speed of light.  In philosophy, while new theories must comply with existing theories, there is clearly much less testing/retesting.  So, how does philosophy fit into this framework while maintaining the rigor required for scientific inquiry?  Are there any examples of philosophical discussions that have significantly influenced or changed scientific theory? How do I activate Dauntless Cathar's ability? has the following ability:     {1}{W}, Exile Dauntless Cathar from your graveyard: Put a 1/1 white Spirit creature token with flying onto the battlefield. Activate this ability only any time you could cast a sorcery.   Please clarify. If the card is IN my hand, how can I exile if FROM the graveyard if it is not there? Did the writers mean SEND it to graveyard, or actually exile it? Confused, the writing does not make sense. Selling a car with a lien I own a car personally, but it is mortgaged to a bank. I want to sell it to an individual. I haven't the funds to repay the loan until I'm paid for the car. The buyer doesn't want to pay me without a lien release (or guarantee that one is coming). The bank won't release the lien until it gets the funds. What do people do in a case like this? It must be a common case. What should I do? Is there any difference between being ill and sick?