Periodic Definition and 411 Threads

Recently ( http://arxiv.org/abs/0903.3680 ) has been pointed out a relationship between QM and periodic dynamics, generalizing the old approach to QM due to de Broglie at.al. In particular it is claimed that imposing periodic boundary conditions to a field (on flat spacetime in the free case)...

i just studied S.H.M and i am wondering is the displacement equals the amplitude or zero after the periodic time? because when i thought it equals zero at first because the periodic time is time required for the object to make acomplete oscillation and return to it's starting point right? but...

Homework Statement Let n/m be a positive rational number in lowest terms. By examining the long division algorithm, show that the decimal expansion of n/m is eventually periodic, and that the period divides phi(m). For simplicity,you may assume that (m, 10) = 1. Homework Equations...

Homework Statement The desert temperature, H, oscillates daily between 40 degrees F at 5 am, and 80 degrees F at 5 pm. Write a possible formula for H in terms of t, measured in hours from 5 am. The Attempt at a Solution The best I can come up with is H=60+40sin((pi/6)t) but this...

arXiv:0901.3173 [pdf] Title: Whilst this Planet Has Gone Cycling On: What Role for Periodic Astronomical Phenomena in Large Scale Patterns in the History of Life? Authors: B.S. Lieberman, A.L. Melott (University of Kansas) Comments: 39 pages, 5 figures, to be published in the Biosphere...

Homework Statement By direct substitution, show that equation (3) is a solution of the differential equation (2). Homework Equations (2) (d^2 θ)/(dt^2 )=-g/l θ (Second derivative of θ(t)=-g/l θ.) (3) θ(t)=θ_0 cos⁡(√(g/l) t) The Attempt at a Solution I...

what is the cardinality of a set A of real periodic functions ? f(x)=x is periodic so R is subset of A but not equal because sin(x) is in A but not in R. hence aleph_1<|A|.

Hello, I am currently dealing with Fourier Series, and a question about the period length of a product of two periodic functions is bothering me. If you have two different periodic functions with different (or the same) period and you sum them up, what happens to the period? Can this generally...

Hi guys.. I was wondering are all waves periodical? I mean is periodicity an intrinsic characteristic of a wave? Thanks, Ed.

Homework Statement A particle P of mass m moves on the x-axis under the force field with potential energy V=V0(x/b)4, where V0 and b are positive constants. Show that any motion of P consists of a periodic oscillation with centre at the origin. Show further that, when oscillation has amplitude...

I am wondering if somebody can please help me to locate a very accurate, complete periodic table. Specifically, I'm looking for one that is color, contains electron configurations, and is up-to-date and accurate to the typical number of decimal places. I've searched Google and was not happy...

Homework Statement Considering the periodic boundary conditions (given below) I am supposed to find the solution T(x,t) with the initial condition T(x,0)=\delta(x) Also I am limited to use method of images so I can't use separation of variables unfortunately. Homework Equations The boundary...

Hi, I have a choice of taking this advanced ODE course, and I am wondering if this is worth studying. The course will cover mainly chapter 9 of Boyce/DiPrima textbook after we cover existence and uniqueness theorem. Chapter 9 is called "Nonlinear Differential Equations", and covers topics...

Homework Statement Hi all. Can you confirm these statements: 1) If I integrate an odd, periodic function of period 2L over one period, then the integral equals zero. 2) If I have a function f(x) with period 2L, then f(x+alfa), where alfa is an arbitrary number, will not change it's...

Free Electron Model: Why periodic boundary conditions and what is "L"? Right, hello! The quantum free electron model for electrons in solids (in One dimension) says we need to use periodic boundary conditions such that if Y(x) is the wavefunction, then Y(x) = Y(x+L). Where L seems to be...

Homework Statement We have a piecewise continuous function and T-periodic function f and we have that: F(a) = \int_a^{a + T} {f(x)dx} I have to show that F is diferentiable at a if f is continuous at a. My attempt so far: I have showed that F is continuous for all a. If we look at one...

Apparently, by what I read, the pressure intervals are 90 degrees out of phase with the displacement intervals for a sound wave. How is that so? When the medium is compressed, shouldn't the pressure be at a maximum and when at rarefactions, shouldn't the pressure be at a minimum?

:frown: Hello, guys. I need help. My professor ask us to search for the 20 scientists who prepared the Periodic Table. Well, so far, I only found 10 scientists. 1.Aristotle 2.Antoine Lavoisier 3.Jöns Jakob Berzelius 4.Johann Döbereiner 5.John Newlands 6.Lothar Meyer 7.Dmitri...

From the University of Nottingham, a video series on the 118 elements. http://news.bbc.co.uk/1/hi/sci/tech/7507986.stm Their website: http://www.periodicvideos.com/ And their YouTube channel: http://youtube.com/user/periodicvideos

Homework Statement Starting from the wave function of free electron and applying first order approximation of time independent perturbation theory find wave function of electron in periodic potential. Homework Equations Potential energy in reciprocal space E_{p}(\vec{r}) = \sum_{\vec{g}...

I had actually posted this question earlier below one of my other questions but I am pretty sure it was hidden and no one saw it because it was nestled under a few responses... so here: A periodic wave has the equation .15m*sin(10t+(pi)x) Now i am getting a little bit mixed up about how...

is there a better way to chart elements? surely chemicals characteristics don't behave by atomic number

this has to do with music and notes and soundwaves and stuff i have to find out the sound waves for thirds (eg c and e or d and f or e and g... u get the picture). its in radians by the way. i figured id worked out the formula for c and the formila for e and just add them but I am not sure...

periodic question?? is cos (x^2) a periodic function, also tell about cos(\sqrt[2]{x}) and what's its period if it is?

Homework Statement What kind of conditions do eigenvalues impose to ensure periodicity? Is it plausible to say that irrational multiples of eigenvalues imply no harmonic oscillations, if so why? Homework Equations The Attempt at a Solution

Homework Statement Element X forms a chloride, XCln which melts at 3\circC. When 0.500 g of the chloride reacts with an excess of acidified silver nitrate, 1.19g of AgCl are formed. Another 0.500g sample of the chloride is heated strongly and chlorine gas is given off. When the residue is...

If an atom with more protons have tighter electron orbitals than atoms with fewer protons, why doesn't the "atomic radius" decrease up the periodic table? Instead it increases, why is this?

arXiv:0804.1747 [pdf, other] Title: The Einstein@Home search for periodic gravitational waves in LIGO S4 data Authors: LIGO Scientific Collaboration: B. Abbott, et al Comments: 29 pages, 19 figures Subjects: General Relativity and Quantum Cosmology (gr-qc) A search for periodic...

Homework Statement A 1.50-kg, horizontal, uniform tray is attached to a vertical ideal spring of force constant 185 N/m and a 275-g metal ball is in the tray. The spring is below the tray, so it can oscillate up-and-down. The tray is then pushed down 15.0 cm below its equilibrium point (call...

Homework Statement Homework Equations How do you know when a given set of initial values for an ODE produce a periodic solution? The Attempt at a Solution I tried playing around with it for a bit and then searching the net but came up with nothing

Hi, I have a question that asks me to explain how you could know if the initial conditions lead to a periodic solution of an ODE but I have no clue right now. I'd appreciate any help. Thanks edit: The question is a bit obscure because I am not sure if they are asking in general of for the...

Hi, I'm looking for an efficient algorithm to solve this kind of equation : S = (1-\nabla^2)B where both S(x,y) and B(x,y) can both be non-periodic functions. We know S and want to find out what is B. I was wondering if there was a 'well known' method to solve this kind or problem in the...

Three parallel, infinite, uniformly charged planes are arranged as shown in Figure 24.32. (it looks just like it's described. The middle plate is positive sigma, the outer plates are both negative sigma.) Homework Statement A small hole passes through the middle plane. At t=0 an...

One thing that's always bothered me about Bloch's theorem is the periodic boundary conditions which are imposed on the system. Clearly, when dealing with an actual solid, the more natural choice would be to impose zero at the boundaries. I know that periodic conditions make the math easier, but...

Homework Statement Is the derivative of a periodic function periodic? Is the integral of a periocic function periodic? Homework Equations a function if periodic if f(x)=f(x+p) The Attempt at a Solution I think that the derivative won't be periodic but the integral will. I'm not...

If not, then what are the conditions for us to construct a periodic boundary condition(PBC)? If so, then please help me construct a PBC for the lattice shape in the attachments. I want to ask that what lattice site m's left neighbor is and what lattice site i's down neighbor is.From the...

in the periodic table we have the density of each element ( density(Si) = 2.33), density(O)=1.429). i wonder how we could calculate the density of SiO2 ?

Homework Statement What information can i find on the periodic table of the elements and what does it mean Homework Equations What is anything. The Attempt at a Solution Atomic symbol, the big letter, for the element abervation. The elements name, for the elements name. Atomic...

Homework Statement If a(t) is periodic and is composition of two signals such that a(t) = b(t) + c(t), then are b(t) and c(t) necessarily periodic? 2. The attempt at a solution I think that b(t) and c(t) must be! Is this correct?

Does anyone here know of a free periodic table (downloadable/printable) geared towards the needs of solid state? More specifically a table offering Lattice constants/crystallization systems, Mean Debye Temperatures etc. Ideally it would be a perfect copy of the periodic table featured by...

[b]1. I was given times for the sunrise in new york for one year. The question was that I needed to find a function that would best represent the data. The first column is the week number and the second is the time in hours and min. 1 7.2 2 7.2 3 7.18 4 7.14 5 7.09 6 7.02 7 6.54 8...

When I was in college years ago, I came across this test question: How will the periodic table of elements look like in another planet? Perhaps, it is asking for a general answer. Do you know if it will change the order of the elements?

Homework Statement Suppose that f(x) is a periodic function with period 1/2 and that f(2)=5, f(9/4)=2, and f(11/8)=3. Evaluate f(1/4), f(-3), f(1,000) and F(x) - f(x+3) (I'm not sure on this one, the teacher never really taught us this, we are on Derivative right now, but this is just one...

Hi all, I am new to this forum. My question is: Find values of b and r for which trajectories are attracted to a periodic trajectory. The function is: f(x) = r*x/(1+x)^b No proofs needed, just a numerical demonstration. Thanks a lot, Ljilja

Homework Statement For the periodic signal x(t)\,=\,2\,+\,\frac{1}{2}\,cos\left(t\,+\,45^{\circ}\right)\,+\,2\,cos\left(3\,t\right)\,-\,2\,sin\left(4\,t\,+\,30^{\circ}\right) Find the exponential Fourier series.Homework Equations Euler’s Formula...

Homework Statement If x(t) is a periodic signal with period T, show that x(at), a > 0, is a periodic signal with period \frac{T}{a}, and x\left(\frac{t}{b}\right), b > 0, is a periodic signal with period bT. Homework Equations HINT: Define x_a(t)\,=\,x(at) and...

Is there well known solutions to a differential equation \Big(-\frac{\hbar^2}{2m}\partial^2+U\cos\big(\frac{2\pi x}{L}\big)\Big)\Psi(x)=E\Psi(x)?

for the solution to the time-independent Schrödinger's equation with a period potential, V(x)=V(x+a) one has: \psi(x)=Af(x)+Bg(x) and \psi(x+a)=A'f(x)+B'g(x) the coefficients are related by a matrix equation, let v=[A, B]^T v'=[A', B']^T then v=Kv' where K is some non-singular matrix...

Homework Statement Use the periodic table to write the electron configuration of Gd. Homework Equations The Attempt at a Solution Gd has 64 electrons (atomic number 64) so I would assume that the configuration would be: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f8 5s2 5p6 6s2...

Nowhere in my notes does it say what Eθ is and i can't find a definition of it on the internet :confused: I'll give you the context: For group 2 of the periodic table, state and explain the trends in the following for their elements: (i) redox property, related to Eθ value