Infinite Definition and 1000 Threads

In a lecture I heard that if we suspend two objects of different masses (and the system is accelerating) on both sides of a pulley of no resistance with a mass-less string then the tension on both sides of the string is same - this is fine till now. To explain that the tension is same, it was...

Homework Statement We have an infinite slab of conducting material, parallel to the xy plane, between z = −a and z = +a, with magnetic susceptibility χm. It carries a free current with volume current density J = J0z/a in the x direction (positive for z > 0, negative for z < 0). The integrated...

Hello, a dubt arose while doing some exercise. If I have a charge q at a distance d from the above-mentioned plane, i can find the solution to the laplace equations (thanks to the uniqueness theorems) finding a collection of image charges that satisfies the boundary conditions. These conditions...

İn a finite set, can we take limit to $\infty$ ? Also, can you give an example related to infinite subset of $\Bbb{N}$ ?

The quantum states ##\psi(x)## of the infinite square well of width ##a## are given by ##\psi(x) = \sqrt{\frac{2}{a}}\sin\Big(\frac{n \pi x}{a}\Big),\ n= 1,2,3, \dots## Now, I understand ##n \neq 0##, as otherwise ##\psi(x)## is non-normalisable. But, can't we get additional states for...

Homework Statement hello this question is discussed in 2009 but it is closed now If you invest £1000 on the first day of each year, and interest is paid at 5% on your balance at the end of each year, how much money do you have after 25 years? Homework Equations ## S_N=\sum_{n=0}^{N-1} Ar^n##...

If there is a small object with positive charge placed above a metal plate, the object induces a negative charge on the surface of the plate facing the object. Let's call this surface as S1. (The metal plate is initially uncharged). But from conservation of charge, the net charge in a metal...

Homework Statement I have to find GCD or HCF of two numbers. Homework EquationsThe Attempt at a Solution #include<iostream.h> #include<conio.h> void main() { clrscr(); int i,m,n,temp; cout<<"Enter two numbers\n"; cin>>m>>n; do { if(n>m) { temp=n; n=m...

Hello, I have been reviewing my textbook lately, and I came across a rather paradoxical statements. all of the convergence tests in my book state that the terms of the series has to be positive. However, when I solved this power series ∑(-1)n-1(xn/n), I found that it converges for -1<x≤1, but...

So, in a section on applying Eigenvectors to Differential Equations (what a jump in the learning curve), I've encountered e^{At} \vec{u}(0) = \vec{u}(t) as a solution to certain differential equations, if we are considering the trial substitution y = e^{\lambda t} and solving for constant...

Because a triangle comes out to 180 degrees, and yet it can only have three sides. A circle has 360 degrees, but its number of "sides" are uncountable. Can someone explain this?

So, according to physicsoftheuniverse.com, "In the centre of a black hole is a gravitational singularity, a one-dimensional point which contains infinite mass in an infinitely small space, where gravity become (sic) infinite and space-time curves infinitely, and where the laws of physics as we...

Homework Statement Suppose we have a infinite cylinder of radius=R and with uniform volume charge density ρ. Use Maxwell's Equations or relationships from them to find E, B, V, and A everywhere. Pretty easy. But how do you approach the problem when you bring an angular vel into the mix...

Homework Statement A long straight wire carrying a constant current I1 and a circular wire loop carrying a constant current I2 lie in a plane. The radius of the loop is R, and its center is located at distance D from the straight wire. What is the magnetic force exerted on the loop by the...

Homework Statement An infinitely long wire carrying a 1 A current in the positive x direction is placed along the x-axis in the vicinity of a 5-turn circular loop located in the x-y plane as shown in the figure. If the magnetic field at the center of the loop is 0, what is the direction and...

1. The problem statement. for Infinite symmetric well -a/2 < x < a/2 in one dimension show that wave function Ψ = Acos(kx) + Bsin(kx) is not physically accepted solution although its mathematically accepted Homework Equations ∫ψ(x)* ψ(x) dx=1

Could an infinite Universe ever end?

Homework Statement An infinite plane of charge has surface charge density 6.8 µC/m2. How far apart are the equipotential surfaces whose potentials differ by 100 V? In mm Homework Equations E=σ/(2ε0) The Attempt at a Solution So first I solved for E= 6.8e-6/(2*8.85e-12) = 384170.791 then...

I have been given a task to create an interpolating/extrapolating programme. I have completed the programme for linear interpolation (2 points) but now must make it usable for 3 or more points, ie a polynomial of n points. I think I have the equation in general for a polynomial as it is an...

1. Homework Statement Homework Equations P=IV, =I2R =V2/R The Attempt at a Solution For zero resistance, I used P=V2/R formula, and sub. R=0 , power would be infinite. But if I sub. Into P=I2R, power will be zero. The correct answer should be zero. But why do we need to use the second...

Wouldn't the explanation that fits fundamental laws (e.g. Conservation of E) while making the least asumptions be an ongoing bang-crunch-bang...scenario? Why couldn't expansion be eventually reigned in by forces, dark matter and the like - ultimately leading to contraction? Why shouldn't...

Homework Statement This example is from 3rd edition of Griffiths' textbook. Ex. 5.8 on page 226 I understand that by reversing the direction of the current, sign of B is switched. but i can't get it that highlighted part. and why B doesn't have z-component? Homework EquationsThe Attempt at...

Homework Statement hello i have a question to this solved problem in the book " Mathematical Methods for Physics and Engineering Third Edition K. F. RILEY, M. P. HOBSON and S.J. BENCE " page 118 Consider a ball that drops from a height of 27 m and on each bounce retains only a third of its...

Homework Statement Consider a particle in an infinite square well potential that has the initial wave-function: Ψ(x,0) = (1/√2) [Ψ_1(x) + Ψ_2(x)] where Ψ_1(x) and Ψ_2(x) are the ground and first excited state wavefunctions. We notice that <x> oscillates in time. FIND the frequency of...

Mod note: Added code tags 1. Homework Statement in my main I am getting infinite loop iterating over a link list Homework EquationsThe Attempt at a Solution /* * graph.c * * Created on: Oct 8, 2015 * Author: danif */ #include <stdio.h> #include "IntList.h" int main(void) { typedef...

Why in first order logic theories are not possible a demonstration with infinite steps?

I tried the comparison test for one B but not sure if I am right. Think it could also be a ratio test because of the variable exponent. I'm lost totally lost on number one A. Also, I have the answer for the first part of three but don't know how to do the second part of it by comparing. Thanks

Homework Statement Consider a very large (infinite) number of identical pendulums arranged in a row, with each pair separated by a distance d. Each pendulum is a massless rod of length l with a mass m at its end. Identical springs with spring constant k couple each pair of neighbors. What is...

If the infinite monkey theorem provides proofs for the probability of order's emergence from chaos, is there a way to measure the probability of order in our universe i.e. matter/anti-matter, snowflakes, DNA? I just wonder because if there was, you could compare the two values and see if we...

Homework Statement A potential satisfies ##\nabla^{2}\Phi=0## in the 2d slab ##-\infty<x<\infty##, ##-b<y<b##, with boundary conditions ##\Phi(x,b)=V_{s}(x)## on the top and ##\Phi(x,-b)=-V_{s}(x)## on the bottom, where ##V_{s}(x)=-V_{0}## for ##-a<x<0##, and ##V_{s}(x)=V_{0}## for ##0<x<a##...

Hi What would be the mathematical approach for calculating the resistance between two close points on an infinite plane of resistive material? And if the plane was circular/square/rectangular with the two points at the cente?

Homework Statement A particle is confined between rigid walls separated by a distance L=0.189. The particle is in the second excited state (n=3). Evaluate the probability to find the particle in an interval of width 1.00 pm located at a)x=0.188nm b)x=0.031nm c)x=0.79nm What would be the...

I've inherited the code below. It's giving an infinite loop but I can't find what's causing it. This is code originally on OpenVMS written now for AIX. Can you help? SUBROUTINE MREAD3(N_VESSEL,N_TRIP,N_ICNAF,N_SPECIES,N_DELSTR, + N_SETDEL,N_SELSTR,VESSELS_TO_BE_SELECTED, +...

Hi, I was trying to identify some infinite non-abelian groups other than ##GL_n(G)## and also other than contrived groups such as the group: ##G=\big<r,s : r^2=s^3=1\big>## as per...

I Have tried to solve a problem about infinite potential well with a delta well in the middle, but I haven't the results and so I can't check if the proceeding is wrong... My attempt solution: The Schroedinger's Equation is: ##\psi''(x)=\frac{2m}{\hbar^2} (V(x)-E) \psi (x)## so we have...

Homework Statement I Have tried to solve a problem about infinite potential well with a delta well in the middle, but I haven't the results and so I can't check if the proceeding is wrong. I post the steps that I have followed hoping someone can help me to understand. We have a particle in 1D...

Hi, I was going over a paper on infinite databases when I dropped by PF, and realized that the paper was hosted by Springer, with a reputation for being somewhat loose in its rigor. Does anyone know if this is a legitimate area of research, and, if so, some intro papers on it ? While we're at...

Hi. Assume we have a large number of identical boxes of some finite length ##l## and with infinite potential walls. Let's prepare them all in the same momentum eigenstate. Since for eigenstates ##\Delta p=0##, by the uncertainty principle ##\Delta x## should go to infinity. However, since the...

Homework Statement [/B] Five free electrons exist in a three-dimensional infinite potential well with all three widths equal to a 12 angstroms. Determine the Fermi energy level at T 0 K. Homework Equations E = [(h_bar*pi)2/(2*m*a2)]*(nx2 + ny2 + nz2) The Attempt at a Solution Tried using EF...

Questions I have arrive from other forum by request. I asked: Why can't an infinite motionless lattice be stable or even possible? We set the stage with an infinite lattice and an exactly zero cosmo-constant ( which I gather results in infinite Minkowski space ) universe, what happens? Can't a...

I have very little understanding of the Big Bang, but it seems like it would require a finite universe even though there seems to be a scientific consensus that an infinite universe is a strong possibility. How are these ideas compatible? If space started expanding from a small point at a finite...

Do the black holes have infinite mass? If no then how can they have infinite density? Can we suppose that all the universe is orbiting a black hole (as heaviest masses bend the space time most) and loosing energy at some rate ?

Homework Statement For n = 1, 2, ..., let fn be a Lebesgue integrable function [0,1] → [0, +∞) such that (1) ∫01 fn dx = 1 and (2) ∫1/n1 fn dx < 1/n Let g(x) = supn ∈ ℕfn(x). Prove ∫01 g(x)dx = +∞ The Attempt at a Solution Coffee, banging my head against a wall, etc. There's not enough...

I know that space is expanding, so the further away you go from my location, the faster space is expanding, asymptomatically approaching the speed of light. I also know that as relative velocities approach the speed of light, the length of space contracts. From this I come up with a limit for...

I've been making a go at writing out algorithms myself in MATLAB rather than using pre-existing code. I've just attempted to write the Nelder-Mead optimization method and I have hit a stumbling block where the code is now looping infinitely. It seems to have something to do with sorting the...

x+x^2+x^3+x^4... = 14 Find x Could someone please provide an explanation. Thank you

x+x^2+x^3+x^4... = 14 Find x Could someone please provide an explanation on how to solve this?

Following on from this thread. If the universe is infinite and was at the time of the big bang does that not mean that the size and contents was infinite? In other words at the BB there was already infinite amount of galaxies. I had understood that at, or just after, the BB the mass of the...

In this documentary they discussed some research experiments which concluded that the universe is infinite. I didn't really understand it. Can someone explain how we know that the universe is infinite? Wouldn't this also mean that the universe was infinite at the big bang?

Homework Statement Consider a one-dimensional, nonrelativistic particle of mass m which can move in the three regions defined by points A, B, C, and D. The potential from A to B is zero; the potential from B to C is (10/m)(h/ΔL)2; and the potential from C to D is (1/10m)(h/ΔL)2. The distance...