Finite Definition and 1000 Threads

Hi, I'm not sure if this is the right section, but I'm talking about numbers :). The questions is as written in the title: Is a number preceding infinity, finite?

Im having a little trouble about how to go about defining this signal. It has a sqrt(-1) in it raised to a power so this is where i get confused. No doubt my poor algebra skills may be holding me back from understanding this problem. The signal is x(k)=j^-k u(k) I need to determine: A...

The Oppenheimer Snyder Collapse into a black hole does it happen in finite time for local and remote observers? Does a trapped surface really form in finite time?

Hello, can anyone explain the full analysis of finite square potential well (bound state and scattering state) if V(x) = -Vo, x <= 0 (region 1) V(x) = 0, 0 < x < a (region 2) V(x) = -Vo, x >= a (region 3) It will be helpful if you can attach the analysis in .pdf format. Thank you in...

Homework Statement Find the condition on the depth of the finite square well such that one finds two even and one odd bound state energy eigenstates, but no other bound state solutions exist. Your answer should appear as a range of allowed well depths, say ? < Vdepth of well < ? Homework...

Can anyone think of an example of an infinite group that has elements with a finite order?

So this should probably go into math's section, but I feel you guys can give me the answer too, since this comes from an EE course(Theory of electromagnetic fields) http://pokit.org/get/2f3e7eef6b38bc75f0023b94976a2997.jpg(1) http://pokit.org/get/fc8658090d67ae0fafe79970021d1518.jpg(2)...

Homework Statement This is primarily a question that I'm trying to program into python. I want to know the potential at some distance (x,y) from the center of a square plane. Homework Equations V = integral (k/r) dq The Attempt at a Solution The way I see this mathematically is a...

I have a question which states that I have to solve Phi using the finite difference method in matlab. Phi = Phi_infinity - Phi_t where Phi_infinity = 1 - e^2 and Phi_t = A(t).B(e) A has the differential for dA/dt = -c^2. A and B 1/e.d/de(edB/de)=-c^2.B where e is a separation...

Straight Line Charge of Finite Length (E Field) Homework Statement Find the expression for the E field at an arbitrary point in space due to a straight line of length l uniformly charged with total charge Q. The ambient medium is air. Homework Equations The Attempt at a Solution...

For an infinite cylinder dV=2*pi*r*L*dr Would dv=pi*L*r*dr for a finite cylinder?

Homework Statement 1)The graph below represents the ground state wave function of an electron in a finite square well potential of width L. The potential is zero at x = 0. The wave function of the electron within the well is of the form A cos( 2πx / λ ) where A is a normalization...

Homework Statement A rod of length L has a total charge Q uniformly distributed along its length. The rod lies along the x-axis with its center at the origin.What is the electric potential as a function of position alon gthe x-axis for x>L/2 Homework Equations V=∫kdq/r = ∫kQ/r dx I'll...

Homework Statement I just took an exam and one of the questions gave us a finite line of charge and asked us to calculate the E-field at a point at a point P to the right of the line of charge. here is a poor sketch [+][+][+][+][+][+][+][+][+][+][+][+]---------------------------------- .P...

Given a partial differential equation, how would one go about implementing the forward finite difference method to the Taylor series?

Hiii heeeeeelp please. I am new here and hope to find a solution and an easy to understand explanation to my problem:confused:. Thank you all :smile: a. A specimen corresponding to a finite plate of width W = 65 mm is made from a steel with a yield strength of 650 MN m^-2 and contains an edge...

Hi. I am trying to express the following in finite differences: [ tex ] \frac{d}{x}\left[ A(x)\frac{d\, u(x)}{x} \right] [ /tex ] If I take centered differences I get: [ tex ] \left{ \frac{d}{x}\left[ A(x)\frac{d\, u(x)}{x} \right] \right}_i = \frac{[A(x)\frac{d\, u(x)}{x}]_{i+1/2} -...

Hi, Do you know the name of this kind of singularity at A ? The function is finite but the left derivative is +\infty and the right derivative is -\infty. http://shareimage.org/viewer.php?file=mt79897bbpxxse1v8pzb.jpg Thanks

Homework Statement If G is a finite abelian group and p is a prime such that p^n divides order of G, then prove that G has a subgroup of order p^n Homework Equations Theorem of Finite Abelian Groups: Every finite abelian group G is a direct sum of cyclic groups, each of prime power...

If a gas will expand to fill the available space (container) does this still hold true if the "container" is the atmosphere? Assuming the gas(es) can escape (either in molecular or in subs - atoms) from the area around the Earth containing our atmosphere this means that the gas is not...

As I understand Energy is finite. This is a problem for me tho as I can see one way to create energy. In fact in my eyes energy is created everyday in are very own solar system. Anyway I want to get some points of view on the subject from others before I make my self a fool because maybe you...

Homework Statement Let q=pm and let F be a finite field with qn elements. Let K={x in F: xq=x} (a) Show that K is a subfield of F with at most q elements. (b) Show that if a and b are positive integers, and a divides b, then Xa-1 divides Xb-1 i. Conclude that q-1 divides...

I'm looking for information regarding the use of the finite element method (FEM) for crash test analysis and crumple zones? Basically I'm wondering what part of FEM do I use to make crash test analysis possible. I'm also looking for books on the subject or software libraries that can be used for...

Homework Statement Prove that a representation of a finite group G is faithful if and only if its image is isomorphic to G. Homework Equations The Attempt at a Solution

In most of the brane world models: our world is supposed to be an infinite thick mathematical surface in the higher dimensional world. Which is very curious. Are there any model in which the thickness of the "surface" is finite? Please, could anyone submit a good paper to me in this topic?

Hey, not sure if this is the correct forum but it seems physics will ultimately bring down the telescope. Why can't we leave the Hubble in space until it doesn't work anymore? It doesn't have any space crew to kill, it would break up on re-entree harming no-one and would continue to inspire our...

This may not be the correct Forum to post this Thread, but i thought i might as well. I was just wondering: if the matter in the Universe is assumed to be 13.75 billions years old, why is it that we can witness things over 13.75 billion light years away? I came across this Wikipedia article on...

I am trying to do a finite element analysis ofcold extrusion process of a tube wherein the steel tube is reduced from a larger outer diamter to a smaller one by extrusion process.The tube is held stationary and the die is pushed into the tube for a particular length and then retrieved.I am...

Homework Statement Consider the equation \dot{x} = rx + x^3, where r>0 is fixed. Show that x(t) \rightarrow \pm \infty in finite time, starting from any initial condition x_{0} \neq 0. Homework Equations I can think of none. The Attempt at a Solution The idea alone of x(t) approaching...

Why must a polynomial be finite in length? Is there such thing as a recursive polynomial? Thanks guys!

Homework Statement If A and B are finite, show that the set of all functions f: A --> B is finite. Homework Equations finite unions and finite caretesian products of finite sets are finite The Attempt at a Solution If f: A -> B is finite, then there exists m functions fm mapping to...

If C is an infinite set and B is a finite set then C\B is an infinite set. C\B means the complement of B relative to C Ok so I was thinking of doing this by contradiction. I have Assume C\B is a finite set. Then there exist a function\alpha that is bijective from C\B to Nk for some k...

Homework Statement What is the probability, that the particle is in the first third of the well, when it is in the ground state? Homework Equations \Psi(x)=Asin((n*pi)/L) A=(2/L)1/2 The Attempt at a Solution so probablility is related to the wave function by \Psi2 so i...

Homework Statement Two masses hang across a massless, frictionless pulley. As the masses become infinitely large, the tension becomes: Homework Equations F=ma The Attempt at a Solution Can someone please help me understand how two masses suspended over a pulley can...

Homework Statement If A and B are finite, show the set of all functions f: A \rightarrow B is finite. Homework Equations Lemma. If A is finite such that |A|=n, then there is a bijective correspondence between A and [n]. *Notation. [n] = \{ 1, ..., n \} The Attempt at a Solution...

Homework Statement Thin rod AB has length L=100 cm and total charge q0=37 nC that is distributed in such a way that its line density \lambda is proportional to the square of the distance from the end A, i.e. \lambda(x) =kx^2. Determine electric field E at the end A of the rod. Homework...

Is it true that any linear map between two arbitrary finite-dimensional vector spaces is continuous? Is it differentiable?

As the thread title says, if the universe is finite will i see my light again. I understand that parts of space-time are expanding faster than c, therefore even in a finite yet expanding universe the light will never reach the "boundry". By boundry i mean more of a turning point where the...

Apologies, the LaTeX thing doesn't seem to be working, so not very clear! I am working through a book on representation theory, but am stuck on these exercises. Homework Statement Let G be a finite group and let E = Sum g (running over all g in G). (i) Prove: Ex = E (forall x in G)...

Is it true that finite sets don't have limit points?

Hi, yet another question regarding polynomials :). Just curious about this. Let f(x), g(x) be irreducible polynomials over the finite field GF(q) with coprime degrees n, m resp. Let \alpha , \beta be roots of f(x), g(x) resp. Then the roots of f(x), g(x), are \alpha^{q^i}, 0\leq i \leq n-1...

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Hello: I am looking to solve a set of 1D PDEs. I thought the finite difference method would be a good way to go about it. So I decided to pick a simple first order forward difference scheme to obtain preliminary results. I just have 1 question: According to my scheme, at the last node...

i am a 3rd year engineering student currently a course in computer methods for structural analysis, as a part of the course we are learning about finite elemnts, we have learned about CST LST Q4 and Q8, but i am having difficulty deciding which element to use for different models. does anyone...

To the EE Forum, I am a new guy on this Physics Forum and this is my first post. I have downloaded a free software code, Finite Element Method Magnetics (FEMM) solver (see http://www.femm.info/wiki/Download) but it doesn’t work because FEMM is limited to solving low frequency electromagnetic...

Hi Sorry for the stupid question, but what is exactly a "stencil" in finite difference methods ? Is the results of the expansion points ? Cheers Alex

Homework Statement From qualitative arguments, make a sketch of the form of a typical unbound standing wave eigenfunction for a finite square well potential. An unbound particle is one which has total energy E greater than the Potential V of the well Is the amplitude of the oscillation the...

Homework Statement Prove that a nonempty set T1 is finite if and only if there is a bijection from T1 onto a finite set T2. The Attempt at a Solution There are at least two different solutions to this problem that I found online...

Hi guys I wish to self-study the Finite Element Method. I am mostly interested in learning how to understand and implement the method rather than to investigate if a solution exists, i.e. I wish to follow the "engineering-approach" rather than the "mathematician-approach". Do you have any...

L={vwv : v,w elements of {a,b}* and |v| =2} I know that "v" can take either aa, ab, ba or bb as values. I also know that "w" can be any string containing "a" and "b". Overall, I know that the two first and two last characters must be identical. How would I show this in a DFA or even an NFA...