I've had to retry this a million times, and it's doing my head in. Please help me.  I resized my partitions from within Windows 8, and disabled everything I was supposed to, I installed 13.04 from a multi-boot LiveUSB. Once installed, I could get into Ubuntu, but not Windows 8. After running boot-repair from Ubuntu on my LiveUSB, the machine boots into this error:     error: file '/boot/grub/i386-pc/normal.mod' not found.   And it gives me the grub-recovery thing.  How do I get this working? At the moment I can have only Windows installed, or only Ubuntu. I want both.
error: file '/grub/i386-pc/normal.mod' not found. grub rescue&gt;   What can I do? I just sit and stare at it.   I found my old netbook (Dell Inspiron 1010) which I have not used for about four years. I replaced Windows XP with Ubuntu 12.10. I used my bootable USB drive. I installed and rebooted. I got the message that normal.mod is not found.   What should I do? Type exit, reboot, or quit? Should I re-install?
CSS transition shorthand with multiple properties? jQuery autocomplete tagging plug-in like StackOverflow's input tags? What is the correct JSON content type? I've been messing around with  for some time, just pushing it out as text and it hasn't hurt anybody (that I know of), but I'd like to start doing things properly.  I have seen so many purported "standards" for the JSON content type:  application/json application/x-javascript text/javascript text/x-javascript text/x-json   But which one is correct, or best? I gather that there are security and browser support issues varying between them.  I know there's a similar question, , but I'd like a slightly more targeted answer. I have installed Ubuntu on my laptop and now I want to remove it and the Grub Loader. How I can do it without the Windows installation disk (I cannot use the Recovery Console). I am looking at the 4-vector treatment of special relativity, but I have had no formal training in Tensor algebra and thus am having difficulty understanding some of the concepts which appear.  One such concept is the notion of contra- and co-variant vectors.  describes a contra-variant vector as varying with the co-ordinates, i.e. the inverse of the reference axes. It gives the example of a change of basis matrix $\mathbf{M}$, and a contra-variant vector $\vec{v}$ and states that in the new set of co-ordinates, we have:  $$\vec{v}'=\mathbf{M}\vec{v}$$  It then states that a covariant vector varies with the co-ordinate axes.     Does this mean that for a covariant vector $\vec{u}$ and change of basis matrix $\mathbf{M}$ we have: $$\vec{u}'=\mathbf{M}^{-1}\vec{u}?$$   I am also having problems understanding the concept of raising and lowering indices. For instance, Wikipedia states that for two four-vectors $\vec{A},\vec{B}$ and using Einstein summation we have:  $$\left\langle \vec{A} \middle|\vec{B} \right\rangle=A^{\mu}B_{\mu}=A_{\nu}B^{\nu}$$  And I am having difficulty understanding how this relates to the other definition of the inner product:  $$\left\langle \vec{A} \middle|\vec{B} \right\rangle =\mathbf{A}^{T}\mathbf{\eta}\mathbf{B}$$  If anyone could help give me a more intuitive understanding of these concepts I would be grateful. During a sunny day the walls of my house warm up (no surprise). My question: how much of this warming up (if any) comes from visible light? I associate infrared with thermal energy. If my house was floating in space (to prevent any thermal exchange with its surroundings) and I installed a giant infrared (and UV) filter between it and the sun, would it still warm up (compared to its rest temperature in full darkness)? Finding the expected value of a continuous random variable with a polynomial function. Update finding the integral. An insurance company's monthly claims are modeled by a continuous, positive random variable $X$ whose probability density function is proportional to $(x+1)^{-4}$ where $0 \lt x \lt \infty$   I need help understanding the reasoning behind the answer:  the PDF is given by:  $1 =\int_0^{\infty} \frac{k}{(1+x)^{-4}}$   Here is my first issue in the first step, where does K come from? We are given the pdf to be $\frac{1}{(x+1)^{4}}$ So to me it would stand that the function we are given is the PDF because it says thats the pdf, and we are then to find the expected value from here which would be equivalent to:  $\int_0^{\infty} x(1+x)^{-4}$ by definition of expected value  My guess would be that the words "proportional to" are key as to why we have a K introduced can someone explain this?  I understand everything except when taking the integral because and solving for 1 because I arrive at $\frac{3k}{(1+x)^4}$ rather than $\frac{-1}{3(1+x)^4}$  Taking the integral of $(1+x)^4$:  $u=1+x$ $du=1dx$ and   $\frac{u^{-4+1}}{-4+1} dx$  which gives $\frac{-3k}{(1+x)^3}$  Which gives me $k=\frac{1}{3}$ when solving $1=\frac{-3k}{(1+x)^4} \Big\vert_0^{\infty}$ rather than $k=3$ as the answer which is the correct answer. Can someone please explain this to me? Let $f(x)\in C^2:[0,1]\rightarrow\mathbb{R}$ satisfy $f(0)=0,f(1)=1,f'(0)=f'(1)=0$, prove that: $$\max_{x\in[0,1]}|f''(x)|\ge4$$  By using Taylor series I can prove that $\max_{x\in[0,1]}|f''(x)|\ge2$, but I cannot go further. Coefficient growth in the power series $\sum u_n z^n = e^{1/(1-z)}$? In all shells I am aware of, rm [A-Z]* removes all files that start with an uppercase letter, but with bash this removes all files that start with a letter.  As this problem exists on Linux and Solaris with bash-3 and bash-4, it cannot be a bug caused by a buggy pattern matcher in libc or a miss-configured locale definition.  Is this strange and risky behavior intended or is this just a bug that exists unfixed since many years? How to space columns evenly in a table with multicolumns? Unable to install "": snap "" has "install-snap" change in progress I just finished the installation of the Ubuntu 18.04, but whenever I try to install any application from Ubuntu Software the same error occurs (for example "vlc"):     unable to install "vlc": snap "vlc" has "install-snap" change in progress   I hope somebody can tell me what I've done wrong. Are used Schengen/UK visas acceptable for Turkish e-visa My Android phone is completely reset, whats the best way to recover the deleted data? How to catch creation of DOM elements and manipulate them with jQuery I have the Blender 2.8 version from the 21st Sep 2018 I was looking forward to render a test sequence but cannot find a render button anywhere? Does anyone know where to find it? How can super massive black holes have a lower density than water? I heard on a podcast recently that the  at the centre of some galaxies could have densities less than water, so in theory, they could float on the substance they were gobbling up... can someone explain how something with such mass could float?  Please see the below link for the podcast in question: Is there a term for solving a sub-sub problem of a problem so far removed from the main problem the link is not clear? In some situations, trying to solve a problem uncovers another problem. Attempts to fix that uncover yet another. A few more rounds and one can be doing something seemingly completely unrelated to the main problem. Is there an expression for that? As much as I have tried, it doesn't seem possible to use separate labels when using a casesconstruction (from the amsmath package).  Ideally, I would like to be able to write something like  \documentclass{article} \usepackage{amsmath} \begin{document} \begin{equation} f(x)=\begin{cases}   1&amp;x\geq0\label{positive}\\   0&amp;x&lt;0\label{negative} \end{cases} \end{equation} \end{document}   and later refer to both cases at different places. What would be the best way to achieve this result? How to delete files listed in a text file