Periodic Definition and 437 Threads

First of all, HI! This is my first post and my first day in this forum. =) I am having quite a problem demystifying this function. It's on a book I have and it clearly states that it isn't periodical. I can't reach that conclusion and was hoping you could help me out. So, the function in...

Homework Statement I am given this function f(x) = \left\{\begin{array}{cccc} x^2 \ \mathrm{where} \ \frac{-\pi}{2} < x < \frac{\pi}{2} \\ \ \frac{1}{4}\pi^2 \ \mathrm{where} \ \frac{\pi}{2} < x < \frac{3\pi}{2} \end{array} Doesn't this mean that the function is periodic Fourier...

"Is f(x)=sin(x2) periodic? Answer: no." WHY? I believe "sin" is always periodic? Can someone please explain? Any help is appreciated!

Hi all, Everything is in the pdf file. I did the question, but I'm not sure if its correct. My lecture is using Wiley, and I think it is really confusing service for assignments. Anyways, my questions are: Is the question done out right? Why is there θ given, if I don't really need to...

According to our textbook "..every periodic motion, however complicated it may be, can always be resolved into simple oscillatory components." Can someone explain this? How can the periodic motion of Earth be resolved into oscillatory components?

Homework Statement We have been provided with a graph of a function modeled by F(t)=a-aU(t-1)+(-3/2.5*t+4.2)U(t-1)-(-3/2.5*t+4.2)U(t-3.5) I have entered this into MATLAB and it replicates the graph we have been provided with but we now need to extend this as an Even function.

someone told me that there's a proof that says f(x) = x can be expressed as a sum of two periodic functions.. does anybody know this? thanks for sharing

How do you know how many valence energy level you have by just looking at the periodic table? because you know that the group number tells the valence electrons right. :) so what about valence energy level? :D

I got the following PDE. {\frac {\partial }{\partial t}}u \left( y,t \right) = \nu \cdot {\frac {\partial ^{2}}{\partial {y}^{2}}}u \left( y,t \right) With boundary conditions: y=0: u(0,t)=0 y=h: u(h,t)=U_0 \cdot cos(\omega \cdot t) Now I need to show by using substitution that...

It is not a home work. Let us suppose that at t=0 a particle is at rest. At t=0 we switch on a periodic force F(t) = F0sin(ωt). Without integrating the Newton equation, do you think such a force is capable of displacing the particle to very far places as the time goes on?

OKay so here are two examples: let say 1) f(x) = cos 2x + cos x how do you determine whether this function is periodic? I know I have to find period for each cosine. The first one is pi and second is 2pi. Then what do you do? And eventually, how do you determine the fundamental period...

Homework Statement s(t)=13*cos(2000*pi*t + 100*sin(8*pi*t)) Determine the fundamental period of this signal, i.e., the shortest period. Homework Equations x(t)=A*cos(2*pi*f(c)*t + a*sin(2*pi*f(m) + phi)) A=13; f(c)=1000; a=100; f(m)=4; phi=0 Inverse Euler's - A*cos(omega*t + phi) =...

Dear friends, I am a new member of physics forums, so this is may new message. Already thanks to you for your helps to my question. I research some applied mathematician problem's numerical solutions. There are initial-boundary value problems. I need an initial condition function which must...

cos and sin are periodic at 2pi How about tan?

Could someone plase hep me with normal coordinate substitutions with periodic boundary conditions, I can't see where the 1/N cancels in the attached file Thanks Doug

Hello, correct me if I am wrong, but as far as I know if 2 functions f(x) and g(x) are periodic with Tf and Tg periods. f(x)+g(x) is also periodic with least common multiple of Tf and Tg. But; what if that least common multiple doesn't exist? is "sin(x) + sin(pi*x)" periodic? there...

Homework Statement Hi and thank you for reading this! Let \left.f(x) = cos(x) + cos\left(\pi x\right) a) show that the equation f(x)=2 has a unique solution. b) conclude from part a that f is not periodic. Does this contradict withe the previous exercise that states if...

Let f: R-> R be a continuous function. Let T>0 be such that f(x+T)= f(x) for all x. We say that f is a periodic function with a period T>0. Use an appropriate substitution to prove that for all real numbers a \int^{a+T}_{a}f(x)dx = \int^{T}_{0}f(x)dx. I have no idea how to do this...

Hello everyone. I am currently studying the periodic trends in my chemistry I class. So I just want to make sure I understand the concepts. Z effective= Atomic # - # of core electrons. Z increases across a row and doesn't really change going down a group. Size, radius, of atoms the...

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...

Please can anyone tell me how to set this up? I know how to do the required settings in the Physics/Period Conditions. However, to fully implement it, I'm also required to choose boundary conditions in the 2D incompressible navier stokes solver (e.g. wall, inlet, outflow, open boundary...

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...

Using the Schrodinger equation for an electron in a periodic potential where U(r +R) [R is the translation vector R=n1a1+n2a2+n3a3 and ni are intergers and ai are teh primitive lattice vectors, G is for reciprocal lattice G=n1b1+n2b2+n3b3 and ni are intergers and bi= (2PI*aj x ak)/(a1 . a2 x...

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...

Homework Statement Based only on differential equations, discuss why it is unlikely that d^2y/dt = ay with a > 0 has periodic solutions. Homework Equations periodic functions go to infiniti or negative infiniti, differential equations are continuous... The Attempt at a Solution...

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...