Importation multiple dcm images
How to import all files of a folder at once?
Error/warning when using NSolve for simple equation How to zero out a drive? I wanted to change my own password (as an admin) so I did the following command:  sudo passwd   and then it prompted for a password but when I tryed to relog, my password was not changed. I'm now wondering what password did I changed since it did prompted me to enter a password but I'm not sure what password did it changed exactly.  I know that if I do sudo passwd &lt;MY_USER&gt; it works, I'm just wondering without a user what happens.  Thank you Searching for an equation to find the center of a sphere given 4 points, one finds that taking the determinant of the four (non-coplanar) points together with the variables $x$, $y$, and $z$ arranged like so:  $\left|\begin{array}{ccccc} x^2+y^2+z^2 &amp; x &amp; y&amp;z&amp;1\\ x_1^2 + y_1^2 + z_1^2 &amp; x_1 &amp; y_1 &amp; z_1 &amp; 1\\ x_2^2 + y_2^2 + z_2^2 &amp; x_2 &amp; y_2 &amp; z_2 &amp; 1\\ x_3^2 + y_3^2 + z_3^2 &amp; x_3 &amp; y_3 &amp; z_3 &amp; 1\\ x_4^2 + y_4^2 + z_4^2 &amp; x_4 &amp; y_4 &amp; z_4 &amp; 1\\ \end{array}\right| = 0$   yields the equation for the sphere.  Then one need only re-arrange terms into the more familiar form to find the center and radius.  This works fine.  My question is why.    This same approach also works for one or two dimensions.  I'm guessing it also works for finding hyperspheres in higher-dimensional spaces as long as you have a corresponding number of points.  But where did that determinant form come from?  Is there an intuitive meaning for what that relationship is saying? "Much of it is" or "Much of it are"? I'm writing an college-entrance essay and for me it's imperative that I understand and implement the correct one of these two expressions:     "Much of it is" or "Much of it are"   If you need context:     I'm having trouble with my writing. The reason I'm having trouble is that much of it is about....   Should there be an "is" or an "are"? Does a differentiable everywhere function have a continuous derivative? If a function $f$ defined on $[a,b]$ and differentiable everywhere, does it mean that its derivative $f'(x)$ is continuous everywhere on $[a,b]$?  My understanding is 'yes'. Because if there were 'a gap' in $f'(x)$, we could integrate back to $f(x)$ and show that where the gap is, there would be a sharp "angle" where $f(x)$ is not differentiable. Renting a car in Ireland & Great Britain: 1 rental or 2? My wife, two kids and I will be traveling in Ireland and the UK Nov. 1st through 21st. We're flying into and out of Dublin. Our plan is to do a clockwise tour: Fly into Dublin -> Belfast -> Scotland -> England/London -> Back to Dublin to fly home.  We've been planning to rent a car when we land in Dublin (doing just things outside Dublin at the start of the trip) and have a car all the way until London, then turn in the car and take a train/ferry to get back to Dublin before flying home.  However, reading through the car rental section of Rick Steve's 2012 Ireland book is causing us to question if this is the right plan.  He says (p. 480):     If your trip covers both Ireland and Great Britain, you're better off   with two separate car rentals, rather than paying for your car to ride   the ferry between the two islands. On an all-Ireland trip, you can   drive your rental car from the Republic of Ireland into Northern   Ireland, but be aware of drop-off charges ($75-150) if you return it   in the North.   So it seems like he recommends against doing one car rental for both islands, but he also recommends against renting in the Republic of Ireland and returning it in Northern Ireland (our other option for our current itinerary).  So we're not sure which is best here.  A few questions about this:   If we do one car rental all the way from Dublin to London, will there be a similar $75-$150 fee? Is there an easy place to return a car on the Northern Ireland side of one of the Northern Ireland -> Scotland ferries, and an easy place on the Scotland side to rent a car?  We'd like to minimize the number of buses/whatever we need to take between car rentals since we'll be lugging around car seats for both of our children (on top of carrying them and our luggage). Will one way be significantly cheaper than the other?  Besides the basic cost of taking the car on the ferry and the drop-off charges, our credit card will cover insurance in Scotland/England but not in Ireland, so we could potentially get a better rental rate by renting a second vehicle once we're on Great Britain. Although, I know you often get a better rate when keeping a car rental for longer, so that may negate any benefit from the credit card covering the insurance. Making a string out of a string and an integer in Python $P(X<Y)$ where X and Y are exponential with means $2$ and $1$ $x^3-9=y^2$ find integral solutions Find all integral solutions  $x^3-9=y^2$  I tried many times but still no idea how to solve it. I will be grateful for any help. The "Info" bar on top disappeared and the mouse pointer is misaligned I have a problem with Blenders UI. The "Info" bar on top disappeared and the mouse pointer is misaligned. I reinstalled Blender 2 times, deleted every leftover files  but it still does the same thing. This is in v2.78c. The weird thing is that on the bottom everything works fine. Here are some images: Shouldn't this be a pretty straightforward operation? However, I see there's neither a size() nor length() method. Introduction to proofs with a fair amount of hand-holding? The distance between touching objects What is the distance between, say, a cup of coffee and the table it rests on? What is the distance between two touching hands? Is it possible to determine the exact date and time (if possible) of creation of an Apple ID?   Is there any official or unofficial way to establish this if you don't have the initial sign up information recorded? Comparing currency values as floats does not work How to use "who" vs. "that" The MathJax code in Mathematics Stack Exchange doesn't render after I updated to the new version (It used to):     App Version: 1.6.2.5 Device: iPhone 6s OS Version: Version 9.0 (Build 13A342) Chaining the Imperius curse What would happen if a wizard w successfully casts the Imperius curse on a equally powerful wizard a and then order him to cast the same curse back on w?  Follow-up questions.  It is established that casting the curse can be done .  What would happen in the case of a chain of casts that would hit back the original wizard? w-&gt;a-&gt;b-&gt;c-&gt;w  The original wizard could rather command the last wizard c, in the chain, to curse his first target instead. w-&gt;a-&gt;b-&gt;c-&gt;a wich would create a loop of a-&gt;b-&gt;c-&gt;a...  In what kind of limbo would wizards a, b and c exist in?  ( for the sake of simplicity, we can assume that every curse target is not very good at resisting the curse ) How do I sort custom objects alphabetically in an array in Java?