Java 8 appears to be installed but in fact is not (macOS)
Even though JRE 8 is installed on my MAC OS Yosemite, the error - " No Java Runtime present,requesting to install "
if $f^{(n)}(x_0),g^{(n)}(x_0)$ exist and $\lim_{x\to x_0} \dfrac{f(x)-g(x)}{(x-x_0)^n}=0$ then $f^{(r)}(x_0)=g^{(r)}(x_0 )$ for all $0\leq r\leq n.$ Show:   if $f^{(n)}(x_0),g^{(n)}(x_0)$ exist and   $$\lim_{x\to x_0} \dfrac{f(x)-g(x)}{(x-x_0)^n}=0$$   then $f^{(r)}(x_0)=g^{(r)}(x_0 )$ for all $0\leq r\leq n.$   My attempt:  let n = 1,  since $f'(x_0),g'(x_0)$ exists then The taylor polynomial exists: $$T_{f,1}(x)=f(x_0)+f'(x_0)(x-x_0), \lim_{x\to x_0} \dfrac{f(x)-T_{f,1}(x)}{(x-x_0)}=0$$  $$T_{g,1}(x)=g(x_0)+g'(x_0)(x-x_0), \lim_{x\to x_0} \dfrac{g(x)-T_{g,1}(x)}{(x-x_0)}=0$$  Then, \begin{align} \lim_{x\to x_0} \dfrac{f(x)-g(x)}{(x-x_0)^n} &amp; =\lim_{x\to x_0} \dfrac{f(x)-g(x)+T_{f,1}(x)-T_{f,1}(x)+T_{g,1}(x)-T_{g,1}(x)}{(x-x_0)^n}\\ &amp;=\lim_{x\to x_0} \dfrac{f(x)-g(x)+T_{f,1}(x)-T_{f,1}(x)+T_{g,1}(x)-T_{g,1}(x)}{(x-x_0)^n}\\ &amp;=\lim_{x\to x_0} \dfrac{f(x)-T_{f,1}(x)}{x-x_0}-\lim_{x\to x_0} \dfrac{g(x)-T_{g,1}(x)}{x-x_0}+\lim_{x\to x_0} \dfrac{T_{f,1}(x)-T_{g,1}(x)}{x-x_0}\\ &amp;=\lim_{x\to x_0}\dfrac{T_{f,1}(x)-T_{g,1}(x)}{x-x_0}\\ &amp;=0 \end{align}  Then, \begin{align} \lim_{x\to x_0}\dfrac{T_{f,1}(x)-T_{g,1}(x)}{x-x_0} &amp;=\lim_{x\to x_0}\dfrac{f(x_0)+f'(x_0)(x-x_0)-g(x_0)-g'(x_0)(x-x_0)}{x-x_0}\\ &amp;=\left(f(x_0)-g(x_0)\right)\lim_{x\to x_0}\dfrac{1}{x-x_0}+f'(x_0)-g'(x_0) \\&amp;=0 \end{align} I am confused because  $\lim_{x\to x_0}\dfrac{1}{x-x_0}$ does not exist. How can I create an association list from 2 lists? I have a professor at my university who uses content from an un-cited textbook that he has never referenced anywhere, including his green sheet (syllabus), as an additional resource. At least some slides he has used include parts of content that have been re-worded and others that are 100% the same. I noticed this by Googling for textbooks on the material we're studying in class and found that examples given in one that I found were exactly the same as what he has provided.  Would this technically be plagiarism? Should he be given the benefit of the doubt in this situation? Command-line mv exclusion list What are the technical advantages and disadvantages of mirrorless? The main doubt one can have about mirrorless is, I think that they do not provide ttl viewfinder. Is this a big disadvantage? In what way is it worst (or best) than classical reflex system?  What are the others advantages and disadvantages of a mirrorless compared to a reflex?  Have mirrorless a chance to replace reflex (at least for non pros) in the future? How to derive the conjugate prior of an exponential family distribution I am trying to derive the conjugate prior of the univariate Gaussian distribution over both the mean and the precision. I know that the prior I'm looking for is the normal-gamma distribution, but the idea is to derive this result.  It seems that you can write down the conjugate prior of an exponential family distribution immediately if you represent it in the canonical exponential family form.  suggests a way to do just that. So far I have written the Gaussian probability function in this form and equated the following, but I don't see how the form of the conjugate prior is immediately obvious.  $$p(\mu, \lambda | D) \propto p(\mu,\lambda)p(D | \mu, \lambda)$$ If I traceroute to my server via a bunch of different methods, the external ip seems to not work. However the server is online and accessible by this ip.  Localhost:  michaelxu@michaelxu-server:~$ traceroute 127.0.0.1 traceroute to 127.0.0.1 (127.0.0.1), 30 hops max, 60 byte packets  1  localhost.localdomain (127.0.0.1)  0.120 ms  0.069 ms  0.064 ms   Internal Ip:  michaelxu@michaelxu-server:~$ traceroute 192.168.1.3 traceroute to 192.168.1.3 (192.168.1.3), 30 hops max, 60 byte packets  1  michaelxu-server (192.168.1.3)  0.122 ms  0.065 ms  0.067 ms   External IP:   michaelxu@michaelxu-server:~$ traceroute 24.24.174.153 traceroute to 24.24.174.153 (24.24.174.153), 30 hops max, 60 byte packets  1  * * *  2  * * *  3  * * *  4  * * *  5  * * *  6  * * *  7  * * *  8  * * *  9  * * * 10  * * * 11  * *^C michaelxu@michaelxu-server:~$   ...it contines all the way to 30 ... the same thing happens if I traceroute it through the dns server  It also occurs if i do it from another online service:     Tracing route to cpe-24-24-174-153.socal.res.rr.com [24.24.174.153]...  hop rtt rtt rtt     ip address  fully qualified domain name 1   1   1   1       70.84.211.97    61.d3.5446.static.theplanet.com 2   0   0   0       70.87.254.5 po101.dsr02.dllstx5.networklayer.com 3   0   0   1       70.85.127.109   po52.dsr02.dllstx3.networklayer.com 4   0   0   0       173.192.18.230  ae17.bbr02.eq01.dal03.networklayer.com 5   0   0   0       66.109.9.97 ae-11-0.pr0.dfw10.tbone.rr.com 6   41  40  39      66.109.6.208    ae-6-0.cr0.dfw10.tbone.rr.com 7   39  39  40      66.109.6.0  ae-3-0.cr0.lax30.tbone.rr.com 8   37  39  39      66.109.6.65  9   42  40  39      72.129.9.3  agg1.lamrcadq-ccr02.socal.rr.com 10  36  36  35      72.129.10.73     11  53  60  49      24.24.209.18    ge17-0-spsdca1-ars1.socal.rr.com 12  *   *   *            13  *   *   *            14  *   *   *            15  *   *   *          What do the * * * mean? Is there any way to "fix this" Inspired by , say you have a 4x4 two dimensional array, write a function that rotates it 90 degrees. Raymond links to a solution in pseudo code, but I'd like to see some real world stuff.  [1][2][3][4] [5][6][7][8] [9][0][1][2] [3][4][5][6]   Becomes:  [3][9][5][1] [4][0][6][2] [5][1][7][3] [6][2][8][4]   Update: Nick's answer is the most straightforward, but is there a way to do it better than n^2? What if the matrix was 10000x10000? Data   I want operator users on this machine to mount their own cifs shares The sudoers file already contains the /bin/mount -t cifs //*/* /media/* -o username=* command for all operators I want the users to mount a cifs share through a script typing the password only once, not twice. The sudo password and the cifs password are identical.   What I already have  This script works:  #!/bin/bash sudo 'mount -t cifs //192.168.1.1/home /media/$USER/home -o username=$USER'   ...but it requires the users to type the same password twice!     Once for sudo Once for the mount itself   This would also work:  #!/bin/bash echo -n Password:  read -s szPassword echo $szPassword | sudo -S sh -c 'echo $szPassword | mount -t cifs //192.168.1.1/home /media/$USER/home -o username=$USER'   ...but this would require me to allow all operator users to be able to sudo sh (major security problem)  Question  How to mount a cifs share in bash¹ without putting sh in the sudoers file nor creating a permanent/temporary file???  Note 1: no python, perl, C, Go, ... please? Note 2: I know I can just remove the password through the sudoers file, but I'm trying to tighten security, not loosen it, without giving up convenience... I have 2 quartz crystal resonators in my pcb board: 32.768 kHz &amp; 20 MHz. They are connected to a Freescale MC12311 transceiver IC, which has an HCS08 micro-controller embedded in it. I want to test if these crystals are working properly or not.  Available tools: Oscilloscope, Frequency-Meter (Digital Counter), Digital Multimeter.  How should I use these tools to test the crystals in board?   Note: The capacitive load-effect of probes should probably be considered. If not, the measurement would not be accurate, or even worse, the crystals would not work at all.     Edit1: I used both the oscilloscope and the frequency-meter (with x10 probes), but unfortunately there was nothing monitored at all. Currently using Ubuntu 18.04, and my wireless driver is not being detected.  I've included a .  $ dmesg | grep iwl [    6.212724] Loading modules backported from iwlwifi [    6.212724] iwlwifi-stack-public:master:6988:0d8892f2 [    6.224583] iwlwifi 0000:00:14.3: enabling device (0000 -&gt; 0002) [    6.229811] iwlwifi 0000:00:14.3: Direct firmware load for iwl-dbg-cfg.ini failed with error -2 [    6.230540] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-39.ucode failed with error -2 [    6.230547] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-38.ucode failed with error -2 [    6.230552] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-37.ucode failed with error -2 [    6.230557] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-36.ucode failed with error -2 [    6.230562] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-35.ucode failed with error -2 [    6.236670] iwlwifi 0000:00:14.3: loaded firmware version 34.0.0 op_mode iwlmvm [    6.248314] iwlwifi 0000:00:14.3: Detected Intel(R) Dual Band Wireless AC 9560, REV=0x318 [    7.264081] iwlwifi 0000:00:14.3: SecBoot CPU1 Status: 0x3, CPU2 Status: 0x2477 [    7.264084] iwlwifi 0000:00:14.3: Failed to start INIT ucode: -110 [    7.276165] iwlwifi 0000:00:14.3: Failed to run INIT ucode: -110   sudo modprobe iwlwifi returns no output. Show that there is no solution to the congruence $x^2\equiv3\bmod5$.   I'm not sure if the fact that the only numbers divisible by $5$ are those ending in $0$ or $5$ will help&hellip; About compactness and completeness of set $X = \mathbb{R}$ with the metric $d(x, y) = \frac{|x-y|}{1+|x-y|}$ What is the string concatenation operator in Oracle? What is the string concatenation operator in Oracle SQL?    Are there any "interesting" features I should be careful of?    (This seems obvious, but I couldn't find a previous question asking it). The value of $\lim_{n \to \infty}\int_{0}^{1}nx^ne^{x^2}dx$ Why is file transfer speed decreased when copying multiple smaller files? Let's say I'm copying a portable apps directory from PC to an external HDD. An application.exe file is around 4 megabytes in size, but most other files are only tens of kilobytes in size, and most of those files take longer to copy/move than that bigger file having 4 megabytes.  Why is this? When I was at school and learning integration in maths class at A Level my teacher wrote things like this on the board.  $$\int f(x)\, dx$$  When he came to explain the meaning of the $dx$, he told us "think of it as a full stop".  For whatever reason I did not raise my hand and question him about it.  But I have always shaken my head at such a poor explanation for putting a $dx$ at the end of integration equations such as these.  To this day I do not know the purpose of the $dx$.  Can someone explain this to me without resorting to grammatical metaphors? How exactly does curved space-time describe the force of gravity? I understand that people explain (in layman's terms at least) that the presence of mass "warps" space-time geometry, and this causes gravity. I have also of course heard the analogy of a blanket or trampoline bending under an object, which causes other objects to come together, but I always thought this was a hopelessly circular explanation because the blanket only bends because of "real" gravity pulling the object down and then pulling the other objects down the sloped blanket. In other words, to me, it seems that curved space wouldn't have any actual effect on objects unless there's already another force present.   So how is curved space-time itself actually capable of exerting a force (without some source of a fourth-dimensional force)?  I apologize for my ignorance in advance, and a purely mathematical explanation will probably go over my head, but if it's required I'll do my best to understand. How to find which package provides a file? For example, I can't install package qcad because of error: "can't find qdict.h". How can I find the package which provides the file qdict.h so I can install the package qcad? When writing my custom function I need to manually append node name to a taxonomy term link. To get the taxonomy term part done I use:    $link_uri = taxonomy_term_uri($term);   $path_alias = drupal_get_path_alias($link_uri['path']);   This works ok, now - I want to append node name ("/" . $node_name), but instead of raw string, I want the Pathauto transliterated output, as set in the URL alias configuration, for that node context.  What function should I use to mimic that output? I looked at hook_pathauto_alias_alter(&amp;$alias, array $context) but I'm not sure that's what I need.