Why does the sun appear yellow?
Why doesn't the Sun appear green to our eyes?
Using Model to equally distribute points, spatially within known geometry using ArcGIS ModelBuilder? Is it possible to create a model in ArcGIS ModelBuilder where you simply state number of points and an area in the form of a polygon to get the model to try and equally space out the points based on the geometry of the polygon and number of points? I'd like to create a popup list on one of my Visualforce pages, for a user to select from a list of OrgWideEmailAddress records.  My goal is to limit the list to only those records that they're allowed to use.  I'm going to save the selection for use in later automatic emails.  Based on what I've read, I won't be able to send emails to certain OrgWideEmailAddresses:   The address hasn't been verified yet.  I don't see any fields in the schema that appear to show verification state. The address is only available to profiles that the user isn't a member of.  I don't see where the profile list is stored for each record.   Some of my problem could just be due to not understanding the standard objects so well, and perhaps there's a way to get at this through UserInfo, or by making my query on the User object which may have a child relationship to OrgWideEmailAddress since it's listed in the schema viewer of the Force.com IDE.  Here's the test code I'm working with:  for (OrgWideEmailAddress addr : [SELECT DisplayName, Address          FROM OrgWideEmailAddress ORDER BY DisplayName]) {     System.debug( addr.DisplayName + ' &lt;' + addr.Address + '&gt;'); }   I tried creating a new Messaging.SingleEmailMessage and then calling setOrgWideEmailAddressId() on it with each OrgWideEmailAddress Id, in hopes that invalid Ids would throw an exception, but to no avail.  My goal is to modify the test code to provide just the subset of records that the current user will be able to use. This is my first time through playing Elder Scrolls and initially I grabbed every quest that has come available...  At first I thought I wanted to be part of the Imperial Legion but I feel like I picked the wrong side and am now regretting my choice.  So...is there any way to un-join the Legion and join up with the Stormcloaks, or will I have to wait and join them next time? How to get the current branch name in Git? How is it that questions posted to the Stack Overflow show up as #1 in Google search results just minutes after being submitted? What SEO practices are being used to generate this sort of up-to-the-minute accuracy? Is there a reason why "gn" in "reigning" is pronounced /n/ while in "regnant" it is pronounced [gn]? Both reigning and regnant are related to the same Latin noun, regnum.  Why is the ‹gn› spelling pronounced [n] in the first word but [gn] in the second? Combinatorics - binary - very interesting question I tried to solve this problem without any success. I really hope that you will know the answer. $f(n,m)$ presents the number of binary strings (empty string included) that include at most n times '1', and at most m times '0'.      Prove: $$f(n,m) = \binom{n+m+2}{n+1}-1$$ I am able to solve simple differential equations like :  $$\dfrac{dy}{dx} = 3x^2 + 2x$$  We simply bring $dx$ to other site and integrate.  But how do we find solutions of differential equations like :  $$\frac{d^2x}{dt^2} + \dfrac{kx}{m} = 0$$  ?  We have been told the solution is $x(t) = A\cos ( \omega t + \phi_o)$ where $\omega\ =\sqrt{\dfrac{k}{m}}$  but how do we actually find it? If $f'$ is differentiable at $a$ then $f'$ is continuous at $(a-\delta,a+\delta)$ Let $A$ be a square matrix of order $n$ such that $A^2 = I$.  Prove that if $1$ is the only eigenvalue of $A$, then $A = I$. Prove that $A$ is diagonalizable.   For  (1), I know that there are two eigenvalues which are $1$ and $-1$, how do I go about proving what the question asks me? Why is the net speed of Stack Overflow so fast? This question is about the net speed.  I'm from China, and I find that opening pages on Stack Overflow is very fast, normally within a range of 1 to 4 seconds. This speed is very good for a website outside China; it's even faster than some native websites.  Not every website outside China has such good speed, so I am wondering why and how Stack Overflow manages to be so quick. Pacf lag axe , is not an integer Why does editing posts on SO require a minimum of 6 charaters? I have just recently started editing the post on Stack Overflow.  I found some posts which only required 2-3 character changes like they had correct grammar but some mistakes in spelling.  When I tried to correct the spelling mistakes, and clicked on "edit", it said:  Edits must be at least 6 characters   I don't know why Stack Overflow added this limit. How can I edit only 3-4 characters in a post? How do i test capacitors? I've just gotten through replacing capacitors on a trio of dead LCD screens (nothing's blown up yet, so far) - they either had one or two capacitors on their inverter circuit SLIGHTLY bloated, and not quite leaky. I ended up replacing all capacitors of the same brand/'colour', even the ones that looked fine, in case.  Now, checking a bad resistor is simple - i can use a standard multimeter to test it, and i tend to check my solders with the continuity testing option of the multimeter.  How would i test a capacitor ? Is there some standard, common way to test one? I know the usage of     This is a new car.   This is singular.     These are some books for you.   These is plural.  Shall we use   There exists some people who agree with me. There exist some people who agree with me.   Which one is the correct usage and why? Dodecagon Area Question The distance between two opposite vertices of the dodecagon is 2. Find the area of the dodecagon.  Is there any way to do this without trigonometry?  And could you include a proof also? :O I have been racking my brains over how in bloody hell can you have a different header for the title (or first) page of a document.   I am not asking here how I can not have a header by clearing the page style for this page using \thispagestyle{plain} or something of the sort but how can I have a different header just for the very first page.   Please help as I have a deadline to meet.   So far, I have not been able to find anything useful on TeX.SE.   Here is some of my code to give you some idea of what I want to achieve:  \documentclass[12pt]{article} \usepackage{amsmath} \usepackage[margin=2.5cm]{geometry} \usepackage[utf8]{inputenc} \usepackage{amsfonts} \usepackage{fancyhdr} \usepackage{hyperref} \usepackage{graphicx} \usepackage{csc} \pagestyle{fancy} \fancyhead[L]{**Left Header for all pages**}\fancyhead[R]{**Right Header for all pages**} \lhead{**Left Header for just the first page**} \rhead{**Right Header for just the first page**} \title{Problem Set 1}         \author{MyBloodyName} \date{January 31, 2017} \begin{document}     \maketitle     \newpage     Easier? \end{document} Can a child inherit both their parents' clans jutsu? Can a child in Naruto inherit both abilities from his parents' clans?  For example, if Ino and Sasuke had a child is there a possibility for it to have both Uchiha's Sharingan and Yamanaka's mind transfer jutsu? How to convert PDF to (La)TeX? I know that hardly any information is passed to the PDF when a .tex file is compiled.  But is there a tool that can convert a PDF document back to (La)TeX? I'm reading .     The graph of $f: A \rightarrow B$ is the subset of $A × B$ consisting   of all ordered pairs $(a, b)$ with $f (a) = b$. If $A$ happens to be   $B^n$ for some $n ∈ N$, then we say that $f$ is a function on $B$ and   $n$ is the arity of $f$.   I don't understand the notation for the exponent of a set, I'm aware of what  is, it's the number of arguments or operands the function takes. I'm just not so sure if I can assume that a set with an exponent such as in $B^n$ means that a function has two operands.  I know the question may be too naive and perhapes the answer is the one I suggested and it's right in front of my face, I'm just searching for a confirmation or the negation of it. Thanks.