Periodic Definition and 411 Threads

Homework Statement Determine whether or not each of the following signals is periodic if signal is periodic determine the fundamental period (note that these are discrete not continuous signals) Show your solutions 1. x(n) = \cos^3(\frac{\pi(n)}{8}) 2. x(n) =...

Homework Statement Determine whether or not each of the following signals is periodic if signal is periodic determine the fundamental period (note that these are discrete not continuous signals) Show your solutions 1. x(n) = \cos^3(\frac{\pi(n)}{8}) 2. x(n) =...

Is a periodic curve still an immersed submanifold of a manifold M? Suppose y is the curve map an interval to a manifold M, and y is periodic, which means it is not injective. And immersed submanifold must be the image of a injective immersion.

I am asked to prove that a real number is rational if and only if it has a periodic decimal expansion. I have shown that any periodic decimal expansion has an integer p such that multiplication returns an integer. For the case of showing that all rational numbers have a periodic decimal...

Homework Statement Let f be periodic with period P. Prove that 1/f is periodic with period P. The Attempt at a Solution f(s+P)= f(s) I know that is the equation for a periodic function. I am not sure how to prove the 1/f part though. Would I just do this: 1/f(s+P)=f(s)? I'm just...

letsa say my function is: x(n) = 1 + sin((2*pi)/N)*n + 3*cos((2*pi)/N)*n + cos( ((4*pi)/N)*n + pi/2); when i plot it inside a loop, with a loop variable being n, i have something llike increasing slope... even when i set a period N to be 8,4 or whateva.. on the other side... when i plot the...

aka "How to Rearrange the Elements Without Engaging in Alchemy" Below is one view on what the Periodic Table might look like if it were "callibrated" in geometric fashion to the Atomic Numbers of the Earth Alkaline Metals. (red cells) 4, 20, 56 and 120 are all 4 times the sum of squares (1 + 4...

Explain why the melting temperature increases from sodium to aluminium. Why does it have to do with ions and not atoms?

i think jordan wigner transform, when applied to open boundary system, can simplify a spin 1/2 system to a free fermion system but there is a difficulty in the case of periodic boundary condition in this case, we have to deal with terms like S_N^+S_1^-=(-)^{\sum_{k=1}^{N-1}n_k}...

Shall f be continuous function of two real variables. Proof that if equation x''=f(x,x') has not constant solutions, then neither it has periodic solutions.

A long time ago I took a number theory course and really enjoyed it. At one point we were shown the proof for the theorem that a number is rational if and only if it has a periodic decimal expansion. The (<=) direction is really easy if you know some Calculus, but I remember the (=>) direction...

Homework Statement Today i came across this one question where i had no clue of how to proove. it says f(x) = { 1, x rational ......{ ---------------------is periodic but have no period. (Proove it/Show it) .....{ 0, x irrational ignore the dots and dashes., just for indentation...

Homework Statement I am confused with why the author uses this form for periodic sound waves. Why did he use cosine instead? Later, he states Note he uses sin this time. I know that the difference between sine and cosine is the phase offset, by 90 degrees. But why did the...

Dear All, We have an voltage amplifier. The input is given in small square wave steps to check rise time and noise level of an output signal. The rise time looks good, but we see periodic (noise)oscillations after reaching the plateau. We measure signal voltage across capacitor (10 micro...

Homework Statement A firework charge is detonated many meters above the ground. At a distance of 400m from the explosion, the acoustic pressure reaches a maximum of 10.0 N/m2. Assume that the speed of sound is constant at 343 m/s throughout the atmosphere over the region considered, that the...

Consider a dynamic system with a periodic trajectory. Given an arbitrary duration T of time, does there exist a chaotic trajectory of a similar system which approximates the closed orbit for the duration T with a given accuracy? Chaotic orbits which I've seen so far...

Why do metals generally have lower ionization energies than non-metals? I mean, doesn't ionization energy depend on the atomic radius? And the atomic radius is in turn dependent on the shell and the protons. According to these factors, the atomic radius of Sodium should be smaller than...

Please help with periodic motion problems! 1. What are the correct units for frequency? What are the correct units for angular frequency? 2. A grandfather clock keeps time by using a pendulum. If you want to design a pendulum to have a period of 1 s, estimate how long you should make the...

We may observe that cyclical or loosely periodic phenomena are extremely common in nature with phases varying over more than thirty orders of magnitude. Is there some overarching physical principle at work here; some deep line of code in the cosmic program as to why this should be so? This is...

I need to find if Sin(x^2) is a periodic function. As I think its not periodic but I need to proof that. I know that its possible to use f(x) = f(x+T), while T is the period frequency. But how to find out T ? and how to contradict this equation to say that the function is not periodic...

Homework Statement Hi guys Say I have an equation of the form f(x) = cos(x)+cos(0.2x), and I wish to find the solutions x. When I plot this graph, I see multiple solutions, but there is no apparent period for the solutions. Are all the solutions equally valid, or can some be discarded?

How does atomic radii decrease when we move left to right in a periodic table? Though the nuclear charge increase as a result of increase in number of protons,the same increase is occurring in number of electrons.

Homework Statement Consider the power series Σanxn = 1+2x+3x2+x3+2x4+3x5+x6+… in which the coefficients an=1,2,3,1,2,3,1,... are periodic of period p=3. Find the radius of convergence. Homework Equations The Attempt at a Solution My attempt at a solution was to first state...

Homework Statement A water-skier is moving at a speed of 13.3 m/s. When she skis in the same direction as a traveling wave, she springs upward every 6.2 s because of the wave crests. When she skis in the direction opposite to the direction in which the wave moves, she springs upward every...

Hi all - I would like to add a periodic inlet flow rate (Q(t) over an entire period T) as a BC in COMSOL. Does anyone know how to do this in 2D axisymmetric Transient Navier Stokes through COMSOL? I'm aware of the periodic boundary condition option available, but really just don't know how to...

Is an oscillatory motion always periodic ? 3 I think the answer is yes but the answer in my book was NO please explain

Homework Statement 1.If protons and two neutrons are removed from the nucleus of an oxygen-16 atom, a nucleus of which element remains? electron 2. If an atom has 43 electrons, 56 neutrons and 43 protons what is its approximate atoms mass? What is the name of this element? Technetium, 99...

quoted from Kittel text 8th edition page 170,171 the potential energy is U(x)=\SigmaU_{G}e^{iGx} but why it is also equal to-> U(x)=\SigmaU_{G}e^{iGx}+e^{-iGx} from text explanation, i couldn't get it why there is an extra term of e^{iGx} any 1 care to enlight me on this? thanks.

Hi all, let's say I have generated some discrete data as a function of time. And when I plot it, it looks like that it is periodic. Is there any scientific way to check whether or not the discrete data is really periodic? And determine the period, if possible? Many thanks.

Homework Statement Could \[F(s) = \frac{1}{{s(1 - {e^{ - s}})}}\] be the Laplace transform of some periodic function? Why? If so, find that periodic function The Attempt at a Solution If it was the Laplace transform of some periodic function, the the Laplace transform of the first wave...

Greetings, Can you match up the unearthly elements with their earthly counterpart based on the clues? After about 9 hours of work I am stumped. Take a look at the following page: http://www.scribd.com/doc/25315827/Alien-Periodic-Table Please feel free to download as a word doc. I am...

hi, i have a hard problem, i guess so, i am looking for any help g(x) is a bounded Lebesgue measurable function that is periodic i.e. g(x)=g(x+p). Then for every f \in L^1(\Re) lim_{n\rightarrow \infty}\int_{\Re}f(x)g(nx) dx=(\int_{\Re}f(x)dx)((1/p){\int_{0}^{p}g(x) dx) thanks for...

Homework Statement Fourier transform of scaled pulse train from -inf to +inf. Starting at 0 the first impulse is scaled at 2, the second impulse at 1 is scaled as 1, third at three scaled at 2, etc...Homework Equations Does my solution look correct?The Attempt at a Solution X(jw) =...

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

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...

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...