Allow the original poster the option to apply a rejected suggested edit on their own post
User suggested great corrective edit to my answer, but the edit was rejected. What can I do to approve it?
How do I check if a string is a number (float)? What is the purpose of the three part circuit? I'm studying for my final on introduction to circuits and came across a question about this circuit:  The question is:  Identify and describe the three parts of the circuit used for a measurement system for signal conditioning. Describe the signal conditioning one intends to use the circuit for.  From what I can tell the R1 and R2 resistors are the first part of the circuit used to use a fraction of the incoming voltage. The second part is the voltage follower used to move all of the incoming voltage to another circuit. Lastly there is a low pass filter used to filter off the high frequency voltage. The second question I'm not sure of the answer. I think we need a button that says Edit and Close added to the Review Close button options.  Many of these closed posts will be around forever (and should be, closed should not just be a path to deletion), so they need editing.  If I edit it now it goes away, with the only option being a back click to get back to the review, and then click into the post and edit it.  We have an Edit and Reopen button, so this would fit in just fine. How do the PHP equality (== double equals) and identity (=== triple equals) comparison operators differ? Booking travel tickets for visa without paying? Should I always use the perfect present, when the sentence uses "never"? In my English classes, I was taught that never should not be used with past forms, only with present perfect forms; this is also what I read in a grammar book I bought some years ago. (I bought the book in the USA; I guess the book is about American English grammar, but I don't have any reason to believe there is any difference between American, and British English in this case.)  Is it correct to use never with the past tense?     I never said that.        I have never said that. Strange issue with the right side margin Shrink Tempdb log file when reaching a specific size how I can shrink tempdb log file when reaching a specific size?? I'm scheduling job to shrink tempdb but still I face a problem of disk space due to tempdb is full! How to re-enable tray icons for applications in Ubuntu? SQL - an error occurred during the pre-login handshake I want to merge two shape files in which one is of point geometry type and other is polygon type in order to get a single layer containing both points and polygon in a single map. R : constraining coefficients and error variance over multiple subsample regressions Why disable Fast Boot on Windows 8 when having dual booting? Why is everybody keep mentioning to disable Fast Boot on Windows 8 if you have installed alongside Ubuntu? Is it something that is recommended only for UEFI machines or is it a suggestion for Legacy BIOS machines as well? Is it because it makes the Windows partition inaccessible from Linux or there is another more serious reason to disable it? Getting polygon boundaries of City in JSON from Google Maps API? How to install Flash player on Ubuntu? Even though I have the latest Adobe Flash player 11.2 for Linux in Firefox -   - a particular online flash game still requests that I update to the latest flash player.  I've tried this online game on my laptop (Windows 8 with Flash Player 11.8) and it has no problems.  Is there a way to trick Ubuntu or this game into thinking Flash Player 11.8 is "installed"? How resilient is Ubuntu to repeated "power-off" shutdowns? My company is considering the use of Ubuntu as an OS for use on a hardware device.     It would be installed on compact flash drive - apparently this is not standard flash drive but a specific type of memory that is supposed to "cope" with immediate power shutdown (I am not sure how this is achieved but they are supposedly a "high end" card).    The units that would be run using Ubuntu are the type of units that will not be gracefully shutdown - the power cable would be removed and that is that.     Can anybody give me some advice on the potential problems that can occur? Is Ubuntu a good system that can deal with this kind of power outage and reboot successfully on next startup?     I realise that nothing is unbreakable, but is it a commonly used OS for an embedded setup? Is it asking for trouble to use Ubuntu in this kind of environment? In Python, I can compile a regular expression to be case-insensitive using re.compile:  &gt;&gt;&gt; s = 'TeSt' &gt;&gt;&gt; casesensitive = re.compile('test') &gt;&gt;&gt; ignorecase = re.compile('test', re.IGNORECASE) &gt;&gt;&gt;  &gt;&gt;&gt; print casesensitive.match(s) None &gt;&gt;&gt; print ignorecase.match(s) &lt;_sre.SRE_Match object at 0x02F0B608&gt;   Is there a way to do the same, but without using re.compile. I can't find anything like Perl's i suffix (e.g. m/test/i) in the documentation. This is a really weird situation. A guy contacted me regarding a business I have. He offered far in excess of my stated fees and even told me he could help me financially if I needed it, which I do. He said he was a doctor. Before he even showed up, he gave me his bank account and routing number and full name, which I used to pay some utility bills. All the payments went through. He also sent me $2500 through PayPal, and I received an email that I had received the payment, though it's been 24 hours and it still hasn't shown up in my "recent activity" in my account. But at the time when I met him, I had no reason to doubt the whole thing was real.   So we met, and through conversation he seemed totally legit. Halfway through our session, he abruptly left — he claimed he was being called in to the hospital. He had already received some, but not all, of the services we had agreed to. He said he would come back in a few hours. Oh yeah, and since the PayPal funds hadn't gone through yet, and I needed cash to pay rent, he said his "financial advisor" would be wiring me $800 a couple hours later. Well, I never heard back from him and never got a call about a wire transfer. In retrospect it all seems very obviously a scam, except for the fact that he gave me a bank account number that actually worked as far as paying some bills!  My question is, assuming the PayPal payment never goes through — I never got an email saying that it was cancelled, but it isn't showing up in my payments either. I'm planning on calling PayPal if it hasn't gone through by tomorrow. But assuming that payment doesn't go through, how can I use the bank account info to get the payment he promised me as far as the services I provided? Other than paying all my utilities in advance? You'd think with an account number and routing number and full name, I would be able to withdraw money somehow, but I really have no idea how. And since it isn't under my name, I can't make a payment on my student loans. I wouldn't take more than he owed me, but it would really be nice to at least get that, even if I didn't get the $2500 he had promised me.   You always hear about not letting people see your account number and stuff like that, but it seems impossible to do anything with this info even though I have it! If scamming people with their bank account number is so easy, how do scammers do it? So I'm wondering two things:   What legal way can I take what I am owed from this guy? What illegal way do people use this info if they had it? I don't want to get in trouble, but I'm just curious because you always hear how easy it is.   (Oh, and I never actually saw his ID so I don't know that the name &amp; bank info he gave me was actually his, he could have stolen it from someone, though he really didn't seem like a hacker — he was a middle aged black man who was very smart-sounding, polite, soft spoken, and he seemed to have a lot of knowledge that a real doctor would have. I have a college degree and am very skeptical in general and careful about not being scammed and I've never had an experience even close to this, and the whole time I kept thinking "is this guy for real?" but since the utility stuff had gone through, it seemed legit. And nothing he did sent up a red flag like he might be a criminal or something. But later I googled the name and couldn't find a doctor by that name, at least not in the state he said he lives in. And since he said he would be contacting me last night, and he never did, it seems obvious that he planned the whole thing, but it just makes no sense to me.) Computing the Galois group of $x^4+ax^2+b \in \mathbb{Q}[x] $ I want to compute the Galois group of some polynomials, but I want to see some examples first. For example this proposition could be helpful. I don't know how to prove it &lt;.&lt;  Let's consider a polynomial $f(x)= x^4+ax^2+b \in \mathbb{Z} $. Let $ \pm\alpha , \pm\beta$ denote the roots of $f(x)$. Note that $f$ is irreducible iff $\alpha^2, \alpha\pm\beta \notin \mathbb{Q}$. So let's suppose that $f(x)$ is irreducible. Let's denote $G$ the galois group of $f$ (the Galois group of the splitting field $\mathbb{Q}(\alpha,\beta)/\mathbb{Q}$)  $i)$ $G\cong V$ the Klein 4-group iff $\alpha\beta \in \mathbb{Q}$  $ii)$ $G\cong \mathbb{Z}_4$ iff $\mathbb{Q}(\alpha\beta)=\mathbb{Q}(\alpha^2)$  $iii)$ $G\cong D_8$ the dihedral group of order 8, iff $\alpha\beta \notin \mathbb{Q}(\alpha^2)$  I need help with the proofs of this propositions... Well I'm very lost with the computation of Galois group, some care must be exercised, I don't have it. For example I know that Galois group acts transitively, in the sense that $u\in K/F$ a galois extension, the other roots of the minimal polynomial of $m_u(x)\in F[x]$ are precisely the elements $ \sigma(u)$ , where $\sigma \in Gal(K/F)$. And clearly any automorphism, is determined by only the value of a basis. In this case we are working on $\mathbb{Q}(\alpha,\beta)$, so I have to know the values of both. But I have to respect the algebraic relations involving $\alpha , \beta$ I proved that in $i),ii)$ $\mathbb{Q}(\alpha,\beta) = \mathbb{Q}(\alpha) $ So I have to know the values on $\alpha$.   My first question is: If in both cases $i),ii)$, I have an extension of degree 4 (so $|G|=4$) I have to map $\alpha$ to determine the automorphism, but I have also to map $\alpha$ to all of it's four roots. Why the galois group in this case are different?  My second question is about $iii)$ I have no idea How to attack it. I have heard that two permutations are conjugate if they have the same cyclic structure. Is there an intuitive way to understand why this is?