I have added a background image using a tutorial on YouTube. it shows up just fine in my camera view but does not show up when I render the animation or render my viewport. The entire viewport shows up as white
First time I've used cycles rendering engine.  I'm using a movie clip as the background in short animation. Selected RBGA under Property Tab, and Transparent under Film Tab.  It looks good and individual frames in OpenGL active viewport render, and looks fine.  When I try to get it to spit out PNG files of the finished animation the objects render out fine, except no movie clip background as Blender Render engine did when using Paper Sky setting.  Operator error, or am I trying to do something Cycles won't do?  Haven't found an answer in my searches so far.  Can anyone point me in the right direction please.   Addition:  I think I found my problem after a couple more hours of research.  Post should read "operator ignorance" instead of operator error.  Too tired to try the solution tonight, everything looks better in the morning. Thanks anyway.  Sorry, I just saw your posts.  Really tired.  Much appreciation.
Every Function in a Finite Field is a Polynomial Function From a bank of past master's exams I am going through:     Let $F$ be a finite field. Show that any function from $F$ to $F$ is a polynomial function.   I know that finite fields are fields of $p$ elements for $p$ prime [EDIT: It's actually $p^n$ for $p$ prime; see comment below]. Since I have $p$ choices for the $p$ elements to map to, then I have $p^p$ distinct functions. I think every function can be written in the form $f(x) = a_{p-1}x^{p-1} + \dots + a_0x^0$. For then given the values $f(0), f(1), \ldots f(p-1)$, I can solve for the coefficents by the linear system of equations  $$ a_0 + \sum_{i=1}^{p-1} n^i a_i = f(n).$$  This then gives me a $p-1 \times p-1$ square matrix over the field $\mathbb{F}_p$:  $$\left( \begin{array}{ccccc} 1&amp; 0 &amp; 0 &amp; \ldots &amp; 0 \\ 1&amp; 1 &amp; 1 &amp; \dots &amp; 1 \\ 1&amp; 2 &amp; 4 &amp; \dots &amp; 2^{p-1} \\ \vdots &amp; \vdots &amp; \vdots &amp; &amp; \vdots \\ 1 &amp; p-1 &amp; (p-1)^2 &amp; \dots &amp; (p-1)^{p-1} \end{array} \right) \left( \begin{array}{c} a_0 \\ a_1 \\ a_2 \\ \vdots \\ a_{p-1} \end{array}\right)  = \left( \begin{array}{c} f(0) \\ f(1) \\ f(2) \\ \vdots \\ f(p-1) \end{array} \right)$$  If I can show this matrix is invertible, then I can always find the $a_i$. But I am a bit stumped on how to show this (partially because I don't think I've ever done linear algebra in a vector space over a finite field). It does not seem easy to show linear independence, or nonzero determinant, or full row rank.    Alternatively (I just thought of this), can I show this is true by arguing that the map between the two sets (the set of polynomials of degree $p-1$; and the set of functions $F \to F$) is injective, and that it must be a bijection because the sets have the same cardinality $p^p$? Too many SE sites causes confusion have already been created through .  have already completed their beta stage and are waiting for launch.  are in public beta stage.  are in commitment phase in   proposals are listed in   Now it is really confusing to find a suitable site to ask a question. As an example - I host a blog using . Now I have a question about this hosting. I want to post it in a . Where will I post? I have 2 options available now.     Are developers trying anything to solve this confusing matter? How do I start a process from C#? How do I start a process, such as launching a URL when the user clicks a button? How do you compare two version Strings in Java? How do I install the Tor Browser Bundle in Ubuntu? In Ubuntu 13.04 I used to use the ppa:upubuntu-com/tor64  PPA to install the 64-bit Tor Browser Bundle. However, in Ubuntu 13.10 it doesn't work anymore. How do I install the Tor Browser Bundle in Ubuntu? How do I parse command line arguments in Java? What is a good way of parsing command line arguments in Java? Equation of motion of a free particle We know that the equation of motion of particle can be derived from the respective action. But in the book I am reading, the author is saying:     ... timelike worldline of a massive particle is parametrised by proper time, $x^a=x^a(\tau)$. The velocity (tangent) vector is $u^a \equiv \dot{x}^a(\tau)$. This is normalised as $u^au_a =-c^2$.   How can one derive e.o.m? Mark or don't mark required fields if all are required? If all fields in a form are required should they be marked somehow (eg. with an asterisk)?  I see this done a lot and find it redundant?  There could be a difference in big forms and small forms, but in big ones I would add a note at the top that all fields are required, but I wouldn't necessarily do that on small ones.  What do you think is the right approach? Get selected element's outer HTML Comment deletion notification I think you should be notified if anything of yours is deleted or even flagged, preferably with some explanation (even if it's a simple categorisation like #rude, #irrelevant, #incorrect) and who did it.  Recently, a couple of comments of mine vanished without warning or evidence afterwards. I'm fine with deletion, but I think it should be used sparingly and be based on democratic decisions. What's the harm of letting a comment simply sit with no up-votes or responses rather than outright removal? Or allow downvoting and then negatively voted comments are hidden by default?  I get the impression that anything I post could be deleted. Very few people want to be unpopular or do the wrong thing. It takes time to understand what something is about and how best to use it (this site). Whether or not what I posted deserved to be deleted is irrelevant because I got no feedback. No-one can learn without feedback. The number of frivolous comments with many upvotes I've seen shows how inconsistently the rules are applied. A community that gives too much power to highly rated users won't grow but turn stagnant.  Sorry if this was rude, inappropriate or pathetic. I'm aware that similar discussions have occurred. In any case, I'll continue to use the site and move on... Determining user's reputation as of particular date? I would like to programmatically - or with the API determine what a user's reputation is on a particular day. As such, I have found this link:   However, it does not outline a programmatic method to do so. In Lieb and Loss's Analysis, I saw that they mentioned  $L^1(\mathbb{R}^n) \cap L^2(\mathbb{R}^n)$ dense in $ L^2(\mathbb{R}^n)$ (dense wrt the $L^2$ norm, I think). But I didn't find its proof in the book. So I wonder why it is?    Does this conclusion hold for $L^1(\Omega, \mathcal{F}, \mu) \cap L^2(\Omega, \mathcal{F}, \mu)$ for any measure space $(\Omega, \mathcal{F}, \mu)$?  Are there similar statements if replace $L^1$ with $L^p$, and  $ L^2$ with $L^q$ for $p \leq q \in (0, \infty ]$ or $\in [1, \infty]$?  Thanks and regards! My Wi-Fi connection seems to be very weak and the range is very low. It drops by two bars if I just move to the next room and by two if just step outside.  The speed is also not fast as compared to what I get from the router on my desktop .  My laptop is a HP laptop with RTL8723de module. Can anyone help me in bumping up my Wi-Fi speed?  Result of lspci -nnk | grep 0280 -A3:  03:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. Device [10ec:d723] Subsystem: Hewlett-Packard Company Device [103c:8319] Kernel driver in use: rtl8723de Kernel modules: rtl8723de I know that the usual ordering of $\mathbb R$ is not a well-ordering but is there an uncountable $S\subset \mathbb R$ such that S is well-ordered by $&lt;_\mathbb R$?   Intuitively I'd say there is no such set but intuitively I'd also say there is no well-ordered uncountable set at all, which is obviously wrong. I still struggle to grasp the idea of an uncountable, well-ordered set. I recently upgraded to Ubuntu 13.10, with the new keyboard handling system. The little "switch keyboard" option does not let me set it to Alt+Shift. How can I get this keyboard binding, as I have absolutely no interest in using the Mac-esque Super+Space combo? How do I delete unwanted Apple ID's? I'm going thru a phone swap, and I now realize that I have multiple ID's   "codename" "codename@example.com" "realname@example.com"   I've tested all three, and they all have different login passwords. Not sure how I got here but I'd like to clean the mess up.  Is there any way to delete / remove / erase unwanted ID's so they don't exist anymore?  (Note: their existence creates total havoc with any type of ID edit...)  I see from  that I can't merge the apple ID's, but can I simply delete the unwanted ID's? How do people at Hogwarts usually tell the time? Often more than one person contributes to the community coming up with the final accepted answer to a question. However, it is only possible to accept a single answer. Restricting to one final answer does make sense for the sake of referencing that answer later, but in many cases that answer is the product of the input from several individuals. I would like to be able to decide how much of a bounty goes to different users, or some other mechanism to recognize the contribution of multiple users. Of course I could always upvote their previous answers, but this is really incorrect if their previous answers aren't the complete, final answer I've accepted.  What think you metaSOrs? I normally write using the American English forms, but for some particular words, I tend to naturally write it in the British manner (like with the word favourite rather than favorite).  Is it wrong to mix both styles? If not *wrong*, does it looks weird? How to get the spaces properly on the x axis, how to place the y values on the corresponding bars? I am using the following commands to draw a barchart.  \begin{tikzpicture}         \pgfplotstableread{ % Read the data into a table macro             Label       Female   Male               2006-2008    3     1              2007-2009    2     0             2008-2010    9     2             2019-2011    3     3             2010-2012    11    1              2011-2013    6     0             2012-2014    12    7             2013-2015    10    7             2014-2016    10    3         }\datatable          \begin{axis}[         compat=newest, %Better label placement %        axis on top,         ybar stacked,   % Stacked horizontal bars         xmin=0,              % Start x axis at 0         ymax=25,         ymin=0, ylabel={Number of students}, xlabel={Batches},bar width=10pt,         y axis line style={opacity=0},         yticklabels={\empty},         ytick style={draw=none},enlarge y limits={upper, value=0.2},         xtick=data,     % Use as many tick labels as x coordinates         enlarge x limits = .2,         xticklabels from table={\datatable}{Label}  % Get the labels from the Label column of the \datatable         ]         \addplot [fill=yellow] table [y=Male, x expr=\coordindex] {\datatable};    % Plot the "First" column against the data index         \addplot [fill=green!70!blue]table [y=Female, x expr=\coordindex] {\datatable}; %        \addplot [fill=red!80!yellow] table [y=Third, x expr=\coordindex] {\datatable}; \legend{Male,Female}         \end{axis}         \end{tikzpicture}   I got the picture as,     How to get the spaces properly on the x axis? How to place the y values on the corresponding bars? How to rotate the label 90 degree? How to take out the ticks on the top? Is there any other way of representing this data(two dim only)? (optional)   I hope all the questions can be answered in a single answer?