Example Definition and 845 Threads

hey guys, Any one can think of any examples ? Of a sequence of integrable functions{fn} on [0,1] that converges pointwise to a non-integrable function f:[0,1] --> R ??

I'm looking for a function f:[a,b] -> R such that |f| and f2 are integrable on [a,b] any helps?

I need someone to point me towards an instance of a relatively simple QFT problem which illustrates what can be calculated from QFT, how it is calculated, and its physical significance. (Note the qualification "relative". I realize there are likely no simple problems in QFT.) If someone...

Why is it that I can't describe with words the orientation of a 3D object (i.e. I can't give a set of angles that uniquely describe it). On the other hand, I can mimic fairly precisely it's orientation with my hand to describe it. A one dimensional object however, is easy to describe with an...

Homework Statement http://img266.imageshack.us/img266/152/78148531ur5.png Homework Equations A is symmetric. The Attempt at a Solution First of all if you calculate rT you'll get qTA so why it the order reversed in the picture above? Moreover I don't see why it is zero.

can anyone example a function that has limit just in one point

I'm having a hard time understanding example 5.8 in Introduction to Electrodynamics by Griffiths. Why, exactly, is Ienc = KL? It makes sense intuitively, but I don't see how to get this result explicitly -- shouldn't the line integral be along the y-axis, and since \bar{K}=K\hat{x}, shouldn't...

hi, I want to know the practical use of Integration and Differentiation. I know what it is. I just want to know how can i explain it with a practical example. example : for Differentiation - the dy/dx can be explained that y is dependent on independent variable x. How can d2y/dx2 be...

\lim_{x \to 0} x^(1/3) I know that \delta = {\epsilon}^3 the book gives an example: \lim_{x \to 2} (3x - 2) = 4 and you chose \delta = \frac{\epsilon}{3} so 0 < |x-2| < \delta = \frac{\epsilon}{3} implies |(3x - 2) - 4| = 3|x-2| < 3 (\frac{\epsilon}{3}) = \epsilon so i...

What's Example of Lebesgue Integrable function which is not Riemann Integrable?

Talking with a friend about the perpetual motion (we both know it don't exist but don't know how to prove it) I came with the following system. Say you have an almost empty magnet sphere. I say almost because at its center it has a little magnet such that it is repulsed by the internal walls...

Can anyone post me a clear example of how to compute the quotient space U/V from a vector space U and subspace V? I've seen many formal definitions but I'm a little stuck on practical use. I'm particularly interested in an example that shows how U and V being over the reals (for example) can...

Homework Statement I'm trying to develop an expression for the maximum accerlation of a person pushing an object up a slope. I've figured out an expression for acceleration using F = MA based on the forces acting on the person and the object. Now I need to find the max accerlation. We...

How close is this to what is being meant here? Let's say you have a big rubber sheet that can continue to stretch and stretch at the same rate and that it remains flat. (Yes a 2D analogy to help envision a 3D thing). On that sheet are little cars that move over the sheet. These cars...

[SIZE="4"]I have: [SIZE="4"]And how do I get the following matrix with elementary row operations?:

Homework Statement I have a matrix 1, 0, 1/12, 1/12 | 1/12, 0, 0, 0 0, 12, 143/12, 11/12 |-1/12, 1, 0, 0 0, 12, 143/12, 11/12 |-13/12,0,1,0 0, -12, -143/12, -11/12|-11/12,0,0,1...

example 3.30: Let the stress tensor components σij be derivable from the symmetric tensor field φij by the equation σij = εiqkεjpmφkm,qp. Show that, in the absence of body forces, the equilibrium equations are satisfied. I don't have any idea have to solve this problem. Can someone help...

http://img.photobucket.com/albums/v235/gsan_bot/magnetic1.jpg" Refer to example 6.2 shown in the picture, the magnetic flux = -1.2t and the deriative time of magnetic flux should be -1.2, thus, the flux is decreasing and the direction of the induced current should be reverse. but why it say...

Homework Statement Give an example of a convergent series \Sigma z_{n} So that for each n in N we have: limsup abs{\frac{z_{n+1}}{z_{n}}} is greater than 1

Homework Statement This is a worked example from Stewart's Early Transcendentals 6e section 2.7 p. 145 for anybody curious. Let f(x)= \frac{3}{x}. Find an equation of the tangent line to the hyperbola at point (3,1). Homework Equations m = \lim_{h\rightarrow 0}\frac{f(a+h) -...

What are two simple objects that can be modeled as particles? This has me totally stumped...

I think that the speed limit should be strictly enforced. It is horrible that we try to teach teenagers to obey important rules such as no drinking, no smoking, no harassment, no violence, etc but then when they start driving they are bombarded by examples of people blatantly breaking laws going...

Homework Statement Find the recurrence relation and the general term for the solution: y'' - xy' - y = 0 xo=1 Homework Equations y= sum (n=0 to infinity) an (x-1)^n The Attempt at a Solution i get: y= sum (n=0 to infinity) an x^n y'= sum (n=0 to infinity) (n+1)an+1...

can you example a function that is continuous at every point but not derivable

V(x) = \left\{\begin{array}{ll} 0, & \exists n\in\mathbb{Z},\; x\in [2nL, (2n+1)L]\\ \infty, &\exists n\in\mathbb{Z},\; x\in\; ](2n-1)L, 2nL[\\ \end{array}\right. This is a periodic potential. L is some constant. Is a solution \psi(x) = \chi_{[0,L]}(x)\;\sin\big(\frac{\pi x}{L}\big) of the...

Homework Statement I know this is a basic question but this is my first physics course ever and I am having big time trouble, any help is appreciated! Chipping from the rough, a golfer sends the ball over a 3.00 m high tree that is 14.0 m away. The ball lands at the same level from which...

I keep hearing about renormalization in quantum mechanics, frequently in the context of it's mathematical dubiousness. But no-one ever gives an example of this process. Could anyone give an example of a quantity that must be renormalised, along with some context? Even a very general one would do.

I'm not sure the double-slit experiment is one such example, maybe I have not understood it yet. This experiment shows the wave nature of light due to the wavefunctions of photons. But how does it show a particle of zero size that is not just a burst of waves?

Homework Statement Integral from 0 to 2*pi of [(Cos(3*theta)) / (5 - 4Cos(theta))] (d*theta) Homework Equations z=exp(i*theta), Cos(theta) = (z + z^(-1)) / 2, Cos(3*theta) = ((exp(3*i*theta)+exp(-3*i*theta)) / 2 = (z^(3) + z^(-3)) / 2, dz = (i*z) (d*theta) The Attempt...

Hi. I am learning special relativity and have decided to take Einstein's train example to practice some calculations. I have given the train speed v=1/4c and have decided on distances that make the side observer's space and time calculations straightforward. I have calculated everything using...

[SOLVED] Laplace transform, book example I'm having trouble following one of the steps in my textbook. They give a function: y(t) = e^{2t} and plug it into Y(s) = \int_{0}^{\infty} y(t) e^{-st} dt and compute. They end up with: \frac{1}{2-s} \underbrace{lim}_{b -> \infty} e^{(2-s)b}...

I'm battling with first order predicate logic (no identity, no extensions) and currently esp. inference using the so called "natural reasoning" rules for inference. Now, the textbook we use, is very ambiguously defined, even I have spotted several 'errors' in it, the lecturer even more. This...

[SOLVED] Griffiths Example 5.8 Homework Statement This question refers to Griffiths E and M book. In this Example, Griffiths says "the z-component of the B-field cannot possibly depend on the direction of the current in the xy plane. (Think about it!)" I thought about it and thought about...

Homework Statement Give an example of an operator whose matrix with respect to some basis contains only 0's on the diagonal, but the operator is invertible. The Attempt at a Solution I think the operator will not have an upper-triangular matrix since it would then not be invertible.

Homework Statement For each a\in\mathbb{R}, find a function f that is continuous at x=a but discontinuous at all other points. The Attempt at a Solution I guess I am not getting the question. I need to come up with a function, I was thinking of a piecewise defined one, half rational...

http://img211.imageshack.us/my.php?image=img86301qt1.jpg i have a trouble in understanding ROM i know that it has addresses and words and that its used in computers in order to store info. but when i get to the example i can't understand the functionality of it. in the example that i...

[SOLVED] Griffiths Example 3.6 Homework Statement Please stop reading unless you have Griffiths E and M book. In Example 3.6, we must assume that there is no charge inside the sphere even though it does not explicitly state that? Or is that what "hollow" means? Homework Equations...

[SOLVED] Griffiths Example 3.8 Homework Statement Please stop reading unless you have Griffiths E and M book. In Example 3.8, Griffiths makes two claims without justification that I want justification for. First, he says that V=0 in the equatorial plane (I assume this means that x-y plane)...

Hi, Anyone knows a good example to aply Poynting's Theorem? The one thas defines the conversation of energy in the electromagnetic field? Regards Martin

Homework Statement Prove that if a_n>or equal to 0, and sum(a_n) converges, then sum(a_n)^2 also converges. The Attempt at a Solution The only example I can think of is 1/(n^p) where p is any exponent greater than 1. Are there any other examples that I can use or do I only need to use...

I saw somewhere that the act of observing can affect whether light will show its wave nature or its particle nature ie whether the wavefunction will collapse. But then, it seems to me, it's not real observing as in the macroscopic world, we don't just observe, we absorb and therefore destroy...

Hi All, does anyone know how to solve the following first-order non-linear differential equation, a * y' + b * y^2 + c = 0 where a,b,c are scalar constant values. Thanks!

I have an example where a 5v dc source is connected to a 10mh inductor then to 1k and 2k resistors in parallel. In finding the current through the inductor at t=0: written is: IL(0) = 5v / (2/3k) = 7.5 ma what i got was: IL(0) = 5v / (3/2k) = 3.3 ma I'm just checking to make...

http://img214.imageshack.us/img214/3928/idontgetkm1.jpg For example 26, I don't see how (for the 1st part) n=9. In the definition of the summing of them it says n is the number above SIGMA, so why not 10? Is it to do with n=1, which isn't k=0 from the definition?

I'm looking some applied example of Laplace transform. For instance: If I have function f(t) = Asin(ωt + φ), where; A is peak deviation from center ω is Angular velocity t is time φ is phase and now I want to laplace transform it and get some function like...

Simple Robinson Crusoe (RC) economy. There are 2 periods. Price level p is given exogenously (e.g. through trade). RC is the "capitalist," he earns competitive profits (=0) so he is indifferent between producing and not producing. He doesn't have to eat to live. Friday is the laborer, he...

Could someone give and example of a substance that is a Bronsted-Lowry base, but not an Arrhenius base..

What is an example of a sound that is intense but not loud?

I'm aware of plenty of microbes that can cause multiple diseases if present in separate parts of the body: S. aureus causes disease just about everywhere it goes except the surface of the skin and nose, S. pyogenes causes strep throat in the respiratory tract and can be flesh eating if it gets...

How do you take the inverse of a matrix? The specific example I have is A= 1 1 1 1 1 1 1 3 1 1 3 3 1 3 3 3 Find A^-1