Check if username exist/activated in database using MYSQLi
Check to see if an email is already in the database using prepared statements
Is the above statement true? If I have already proven that the set is linearly independent, is it automatically given that the subset is also linearly independent? If so, how would I go about showing that as a proof. I am trying to set up an operator to use the BoolTool after I set a position and modifier on Selected object and a different one on the Active object. I basically need to move the selected object up in Z and add a solidify modifier at .3 thickness, and to the Active I need to add a solidify at .1 thickness and remain in original position.  I thought I understood how to get this to work, but all I get is both modifiers on the Active object. Any hint as to where to go from here?  class SolidfyDifference(bpy.types.Operator): """Solidify and Difference Mask""" bl_idname = "object.solidfy_difference" bl_label = "Add Solidy and Difference Bool" bl_options = { 'REGISTER','UNDO' }  def execute(self, context):     scene = context.scene      sel = bpy.context.selected_objects     act = bpy.context.active_object        for obj in sel:         if obj != act:             bpy.ops.object.modifier_add(type='SOLIDIFY')             bpy.context.object.modifiers["Solidify"].thickness = 0.1        return {'FINISHED'} Can I install any iOS version I wish by picking and choosing which firmware to restore? How can I install applications like Google Chrome on Ubuntu?  Are there any commands to install an application?    Index of answers: How to make text aligned left/center/right in the same line? Particular nodes are missing from node editor I am looking for the  but it is not available under the Vector nodes menu or any other menu. I have Blender 2.77 which cooresponds with the manual version in the above link.    I also cannot find the Texture Coordinate or Gradient Texture.  Likely I am doing something wrong. How to delete empty folder with thumbs.db without disabling thumbnails I often have problem to delete a folder that contains a thumbs.db file. Also tools like  fail. It seems to be loccked by os for some unknown reason. The only solution i found in the net was to disabling thumbnails in windows but this is a bad workaround isn't it?  Is there a "normal"(or official, supported by MS) way to delete an empty folder that only contains a thumbs.db? How is electricity wasted? All i know is electric current travels in a loop. So how / where in its way does electricity (electric energy) get wasted?  And what do we do on switching electric appliances off? If it's not electric current that is wasted then what is it? How to replace text in the body of an incoming message with a hyperlink in Outlook 2010? I have a simple question answer to which would help me more deeply understand the concept of (non)commutative structures. Let's take for example (our teacher's definition of) a ring:  Let $R\neq \emptyset$ be a set, let $\oplus:A\times A \to A$ and $\bullet :A\times A \to A$ be binary operations. Moreover, let $(R, \oplus)$ be a commutative group, $(R, \bullet)$ be a monoid and following property holds for all $a, b, c\in R$: $$a\bullet(b\oplus c) = (a\bullet b)\oplus(a \bullet c)$$ $$(b\oplus c)\bullet a = (b\bullet a)\oplus(c \bullet a)$$ Then ordered triple $\mathbf R = (R, \oplus, \bullet \mathbf)$ is called a (unitary) ring.  Moreover, we call ring $\mathbf R$ commutative iff $(R, \bullet)$ is a commutative monoid. Commutativity of a ring is always a matter of its multiplicative operation because the additive operation is always assumed to be commutative.  Could anyone explain me the bold part? Why do we even in non-commutative rings (and fields etc.) assume the addition to be always commutative? Is there some serious reason? Would it make any trouble? Or studying of structures with non-commutative addition just doesn't give us anything new so we can take addition as commutative simply because of our comfort? How do I read in the contents of a directory in Perl? When a holomorphy ring is a PID? I will use the notation and language of Stichtenoth, Algebraic Function Fields and Codes.  Let $F$ be a function field over a finite field $\mathbb F_q$, $S$ a non empty set of places (possibly infinite) and $O_S$ the holomorphy ring of $S$, i.e., $O_S:=\bigcap_{P\in S} O_P$ (being $O_P$ the valuation ring of the place $P$).  Give necessary and sufficient conditions for $O_S$ to be a Principal Ideal Domain.  Many thanks in advance!  G. What tool can I use to manage the configuration of my Windows Server environments I help manage environments for an application that uses cloud-based Windows server VMs. The application stack consists of Windows Server 2008 and Windows Server 2012, SQL Server 2008, IIS, and SharePoint 2010. I have several environments Dev/Test/Stage/Prod. I am looking for a way to do configuration management of those environments to make sure any environmental changes are applied in a consisent way and there is a way to verify that no changes have been made to one environment that have not been made to other environments.  I have been reading up on Puppet, Chef, etc and I like the idea of doing delcarative configuration management. What is a good method or tool to use to help manage the configuration of these environments. I know a little  about SCCM but it is too expensive for this particular situation although I would still be interested in knowing if it has the capabiltiy to do those things. Select Input Texture file name as parameter/node I am trying to create a material node group for triplanar mapping, but I am not sure how I can parameterize the image texture name.   I have 3 image texture nodes, which all use the same file with the same settings, the only difference is the vector input.  Is there a way I can make it so that I only have to select the texture name once, possibly as a input for a group? Vertical component of moving weight at a 45 degree angle Here's an easier one. I use the leg press machine at the gym so I don't have to worrying about hurting myself while lifting heavier weight.  The weight glides on a track that looks to be 45 degrees.  What's the equation to figure out how much weight I would be able to squat normally.  IE the vertical component of moving 400lbs at a 45 degree angle. Testing for linear dependence among the columns of a matrix I have a correlation matrix of security returns whose determinant is zero. (This is a bit surprising since the sample correlation matrix and the corresponding covariance matrix should theoretically be positive definite.)  My hypothesis is that at least one security is linearly dependent on other securities. Is there a function in R that sequentially tests each column a matrix for linear dependence?  For example, one approach would be to build up a correlation matrix one security at a time and calculate the determinant at each step. When the determinant = 0 then stop as you have identified the security who is a linear combination of other securities.  Any other techniques to identify linear dependence in such a matrix are appreciated. Python dictionary: are keys() and values() always the same order? What is a subnet mask, and the difference between a subnet mask of 255.255.255.0 and 255.0.0.0? My DSL/WiFi router provided by my ISP has an internal IP address of 10.0.0.138, the addresses provided by DHCP are in the format of 10.0.0.xxx.  Now, I want to start using static IP addresses on my local network, and I don't know what to provide for the subnet mask.  What is a subnet mask?  Should I be using 255.255.255.0 or 255.0.0.0 as my subnet mask? What is the difference? POSTFIX main.cf permission denied Let $A$ be a $m \times n$ matrix with entries from some field $F$. Define the determinant rank of $A$ to be the largest possible size of a nonzero minor, i.e. the size of the largest invertible square submatrix of $A$. It is true that the determinant rank is equal to the rank of a matrix, which we define to be the dimension of the row/column space.  It's not difficult to see that $\text{rank} \geq \text{determinant rank}$. If some submatrix of $A$ is invertible, then its columns/rows are linearly indepedent, which implies that the corresponding rows/columns of $A$ are also linearly indepedent.  Is there a nice proof for the converse?