button null object reference
What is a NullPointerException, and how do I fix it?
Prove that $g$ is tangent to the graph of $f$ Should we have a subjective version of every Stack Exchange site? What metadata does a LibreOffice file contain and how to remove it? I have two different list. In the first list are some people picker columns.  Is it possible to create a lookup column for list 2 to add the user from the first list? I know it isn't supported in Sharepoint, but i hope someone have an idea to solve my problem. There does not exist an entire function which satisfies $f({1\over n})={1\over 2^n}$, what I tried is if possible then define $g(z)=f(z)-{1\over 2^{1\over z}}$ Then $g({1\over n})=0$ and so $g(z)$ is entire and its $0$ set has limit point in it and so $f(z)={1\over 2^{1\over z}}$ which is not analytic at $0$? Please help!  Edit: OOps! the way I defined $g(z)$ that is not entire! could any one give me hint? Proof that no polynomial with integer coefficients can only produce primes Doing a discrete math review and am trying to solve problem 1.6 in the text found here:  - I believe I've gotten parts (a) and (b) correctly, but (c) is a bit tricky for me. Would appreciate a review of a/b and a hint for c if possible. Restatement here:  For n = 40, the value of polynomial $p(n)::=n^2 + n + 41$ is not prime, as noted in Section 1.1. But we could have predicted based on general principles that no nonconstant polynomial can generate only prime numbers.  In particular, let $q(n)$ be a polynomial with integer coefﬁcients, and let $c::=q(0)$ be the constant term of q.  (a) Verify that $q(cm)$ is a multiple of c for all $m \in Z$  Proof: Since q is a polynomial, it will be of the form: $q(x) = a_nx^n+a_{n-1}x^{n-1} + ... + a_1x + c$  If $x = cm$, then notice that cm will be inside every term of the polynomial, and since the final term is c, c can be factored out of every term. Hence, q(cm) is a multiple of c for all $m \in Z$.  b) Show that if q is nonconstant and c > 1, then as n ranges over the nonnegative integers, $N$, there are infinitely many $q(n) \in Z$ that are not primes.  Proof: Continuing from the result found in (a), it is easy to see that for all $m \in Z$, there will be an infinite number of multiples of c that will be generated by q. Since c > 1, these multiples are guaranteed not to be prime.  c) Conclude that for every nonconstant polynomial, q, there must be an $n \in N$ such that $q(n)$ is not prime. Hint: Only one easy case remains.  c = 0 is trivially easy to prove using the (b) above.  I assume the "easy" case is referring to c = 1, but in this case I'm not sure how to continue, since the result of (a) and (b) don't apply: I can't use them since adding 1 to any even number may make it prime. If the result of the terms not including c is odd, then adding 1 to that result makes it even and it is not prime. However, if the terms add up to an even number, I don't see a way of using the knowledge I have so far to prove conclusively that that number + 1 will NOT in fact be prime. How do I print all lines of a file with duplicate values in a certain column Let $a_k:=(-1)^k$ where $k\in\mathbb{N}$. $\mathbb{N}$ is the set of all non-negative integer.  And we define the partial sum $S_n:=\sum \limits_{k=0}^{n}a_k$. Notice that the sequence $\{S_k\}$ diverges which also implies that the infinite series $\sum \limits_{k=0}^{\infty}a_k$ cannot be defined.  If I consider the infinite sum $1-1+1-1+1-1+\cdots$, then this statement is equivalent that I just defined the infinite series $\sum \limits_{k=0}^{\infty}a_k$, which is contradiction.  But, suppose that the sum $1-1+1-1+1-1+\cdots$ exists and let the value of the sum be $S$. Then, we can easily observe that $S=1-S$, therefore $S=1/2$. The supposition of this proposition already proved as false, but if I ignore the definition of infinite series, it holds.  Which one is right? Or are these propositions depends on what we define? What is the relationship between Guide Number and flash power level? From this , I understand that the flash guide number (GN) is given by the following formula:  Guide Number = Shooting Distance × f-number ÷ ISO factor   I'm assuming that the GN calculated via the equation above will be based on a flash that is firing at full power. Am I correct to assume that if I set the flash to fire at half power, that the guide number is effectively halved? i.e. the equation will now be:  Guide Number = Shooting Distance × f-number ÷ ISO factor * Power Level   where power level can be the following 1, 1/2, 1/4, 1/8, ... 1/64, etc? I am not sure of the meaning of this sentence:     The significance of culture and identity in development has to do not so much with the cultural factor in the process of development as with abandoning Eurocentric development thinking.   I'm not sure what the use of as is supposed to convey. Does it mean "development has to do not so much ... as with abandoning", i.e. not as much as abandoning? Does the abandoning have more to do with it?  And the second question: Why does it use "has to do not so much". Why not "has not so much to do"? Is "have to" a verb? Search using symbols is broken We used to be able to , but that now appears to be broken.  I'd expect a  to return a result, but instead the search engine appears to put quotes around the whole request; the search box shows the search has been replaced with "[python] += list" and the  I was looking for doesn't appear among the returned questions.  Using quotes around the symbols do not seem to help here;  returns an empty result. Singular or plural verb with two subjects Possible Duplicate:          I'm writing an interrogative sentence questioning someone else's writing:  "Is grammar and spelling correct?"  Can I use the singular verb "is" or must it be the plural verb "are"?  (The sentence is one of a list of interrogative questions about the quality of writing, e.g. "Are words in the right order?" "Does the copy flow?") How can I stop the Devel module from generating blog/forum entries for Anonymous user? I'm using Devel's generate content feature to generate Blog/Forum entries for a site I'm working on and funny enough, I get to have a blog post by an anonymous user or forum topic by an anonymous user.  How can I stop Devel from doing this? I've only given Authenticated Users/ Administrators the permission to create a blog post or forum topic but still it generate for anonymous user. How can correct this? I'm building a Core  system which supports dual-channel memory (up to 16&nbsp;GB in four DIMMs), my target is 8&nbsp;GB. From the performance perspective, is it better to have two times 4&nbsp;GB or four times 2&nbsp;GB? What is this "answer your own question" jazz? I showed up here to write a perfectly normal rant about misaligned pixels, and there's a big fat checkbox cluttering up the "Ask" page:    WHAT THE EEEEK IS THIS NEW ABOMINATION? My computer boots to a black screen, what options do I have to fix it? How can I tell if two pictures were taken with the same camera without metadata? Is it possible to identify images (without exif data) and link them to the exact same camera? If so, I'd like some software recommendations to get the job done.  I have two photos that I'd like to compare whether they were taken with the same camera or not. They both seem to lack EXIF data but I am sure I've heard of other hidden fingerprints to be found within the images.  For instance, sensor noise should be rather consistent if the photos were taken with the same camera, pretty much like firing a handgun and the bullet gets unique marks. I've also heard that the camera manufacturers sometimes add a hidden watermark which can be read with some special software. Prove there are no other solutions of functional equation $f(x+y) = \frac{f(x)+f(y)}{1-f(x)f(y)}$ Nexus 7 2013 error upgrading to 5.0.2 OTA I updated to 5.0.1 via OTA sometime ago, and it worked fine. Now I got a notification that 5.0.2 is ready but when Android shuts down to install update it returns error (with no other message. My Nexus 7 is rooted but has the stock recovery.  Is there an easy fix that doesn't require factory reset or installing recovery? What does role db_owner allow I have been trying to troubleshoot a login that is not able to view certain tables in a SQL Server 2012 database. In doing so I find I don't quite understand what membership in the db_owner role allows. I can understand the other roles such as db_datareader and db_datawriter but I remain confused as to what db_owner allows.