If we were to replace δ(x), the orginal Dirac Delta, with δ(sin(ωx)), what would be the result?
Would we have an infinite spike everywhere on the graph of sinx where x is a multiple integer of π/ω? and 0 everywhere else?
I apologize in advance if I had posted in the wrong category.
Homework Statement
I am trying to derive the following relation using inner products of vectors:
Homework Equations
g_{\mu\nu} g^{\mu\sigma} = \delta_{\nu}^{\hspace{2mm}\sigma}
The Attempt at a Solution
What I have done is take two vectors and find the inner products in different ways with...
Hi again, another question.
Please see the schematic below. It shows a wye-wye(n) with a delta tertiary winding. So this delta winding is inserted here so that we can achieve amp-turn balance with the zero sequence currents flowing on the secondary side.
I know that zero sequence currents...
Homework Statement
Find the uncertainty ∆y in y as a function of the uncertainties ∆u and ∆v in u and v for the following functions:
y = 1/2(u+v)
Homework Equations :
Error propagation formula[/B]
The Attempt at a Solution
Don't know where to begin even. Help?[/B]
Homework Statement
Homework Equations
Power Triangle and 3-phase equations (listed in my solutions)
The Attempt at a Solution
Here are the instructor solutions:
The instructor solutions just go straight into using equations, but I like to use the power triangle because it is more...
I made a few paper airplanes. I noticed that the common paper airplane (shown below)
https://i.ytimg.com/vi/v29M7Oa1l-A/hqdefault.jpg
flies much further/better than paper planes that look like standard 747s. Any know why ?
I expected 747 like plane to be very efficient at generating the lift...
Currently, I am reading this article which introduces electromagnetism.
It gives a function for the charge density as: $$\rho = q\delta(x-r(t))$$
The paper states that "the delta-function ensures that all the charge sits at a point," but how does it do that? Also, if ##r(t)## is the trajectory...
Hi,
Consider this definition of the Dirac delta:
$$\delta (x-q)=\lim_{a \rightarrow 0}\frac{1}{a\sqrt \pi}e^{-(x-q)^2/a^2}$$
First, this would make a normalized position eigenfunction
$$\psi (x)=\lim_{a \rightarrow 0}\frac{1}{\sqrt{a\sqrt \pi}}e^{-x^2/2a^2}$$
right?
If that is so, why do...
Homework Statement
Prove the following
'()( − ) = −′()
∫-∞∞δ'(x)*f(x-a) = -f'(a)
Homework Equations
∫-∞∞δ'(x-a)*f(x) = f(a)
The Attempt at a Solution
[/B]
∫-∞ ∞δ'(x)*f(x-a) = ∫δ(x)*f(x-a)dx-∫f'(x-a)*δ(x)dx = f(-a) - f'(-a)
Went from 1st to second by integration by parts
Used...
Hey, everyone! I'm helping a friend through his calculus course and we've come across something that has stumped me (see: the title). When I learned calculus, our treatment of the epsilon-delta definition of the limit was, at best, brief. Anyway, here is the problem:
Given ##\lim_{x \rightarrow...
Homework Statement
I need to integrate this expression :
P(k, w) = A * δ(w-k*v) * f(k, w)
A is constant and δ, Dirac Delta.Homework Equations
[/B]
There is double integration :
I = ∫0∞ dk ∫0∞ P(k,w) dw
= A ∫∫0∞ δ(w-k*v) * f(k, w) dw dk
The Attempt at a Solution
[/B]
I'm confused with...
Homework Statement
Ultimately, I would like a expression that is the result of an integral with the sin(nx)/x function, with extra terms from the expansion. This expression would then reconstruct the delta function behaviour as n goes to infty, with the extra terms decaying to zero. I...
Is the square of a Dirac delta function, ##(\delta(x))^2##, still a Dirac delta function, ##\delta(x)##?
A Dirac delta function peaks at one value of ##x##, say 0. If it is squared, it still peaks at the same value, so it seems like the squared Dirac delta function is still a Dirac delta...
Homework Statement
Homework Equations
Continuity:
$$\vert x-c \vert < \delta~\Rightarrow~\vert f(x)-f(c) \vert < \epsilon$$
$$\delta=\delta(c,\epsilon)$$
The Attempt at a Solution
$$\vert f(x)-f(c) \vert <\frac{1}{2}f(c)~\Rightarrow~\vert x-c \vert < \delta_1$$
So i have this δ1 but what...
Homework Statement
find a δ for a given ε for f(x)=x3 around c=5:
$$\vert x-5\vert<\delta~\Rightarrow~\vert x^3-5^3 \vert < \epsilon$$
Homework Equations
Continuity:
$$\vert x-c \vert < \delta~\Rightarrow~\vert f(x)-f(c) \vert < \epsilon$$
$$\delta=\delta(c,\epsilon)$$
The Attempt at a...
I just want to make sure that I am understanding the Dirac Delta function properly. Is the following correct?:
For two variables ##x## and ##y##:
\begin{equation}
\begin{split}
\delta(x-y) f(x) &= f(y)
\end{split}
\end{equation}
And:
\begin{equation}
\begin{split}
\delta(x-x) f(x) &=...
Homework Statement
I have a 2D integral that contains a delta function:
##\int_{-\infty}^{\infty}\int_{-\infty}^{\infty}\exp{-((x_2-x_1)^2)+(a x_2^2+b x_1^2-c x_2+d x_1+e))}\delta(p x_1^2-q x_2^2) dx_1 dx_2##,
where ##x_1## and ##x_2## are variables, and a,b,c,d,e,p and q are some real...
Homework Statement
definition of εijk
εijk=+1 if ijk = (123, 231, 312)
εijk = −1if ijk = (213, 321, 132) , (1.1.1)
εijk= 0,otherwise .
That is,εijk is nonzero only when all three indices are different.
From the definition in Eq. (1.1.1), show that...
I'm an undergraduate student, so I understand that it may be difficult to provide an answer that I can understand, but I have experience using both the Dirac delta function and residue calculus in a classroom setting, so I'm at least familiar with how they're applied.
Whether you're integrating...
So if I have a logistic regression: ##log (\hat {odds})=\hat{\beta_{0}}+\hat{\beta_{1}}x##. How would I find a confidence interval for x if I am given ##odds=5## This is going in reverse, where if I have the outcome, I try to do inference on the predictor.
We know that ##\hat{\vec{\beta}}##...
Trying to narrow down what type and size radiator and flow of both the water and air I should be looking at that would give me my best heat exchange efficiencies, if I want to input 50F water into a radiator that will have 100F air (60% RH) blowing through it and my goal here is the cooling down...
Homework Statement
Homework EquationsThe Attempt at a Solution
So cts approx holds because ##\frac{E}{\bar{h}\omega}>>1##
So
##\sum\limits^{\infty}_{n=0}\delta(E-(n+1/2)\bar{h} \omega) \approx \int\limits^{\infty}_{0} dx \delta(E-(x+1/2)\bar{h}\omega) ##
Now if I do a substitution...
Homework Statement
In this problem we shall consider the scattering from repulsive δ-function potentials. We have already considered a single such potential. If the strength of the potential is V0, the transmitted and reflected fluxes may be represented by the transmission and reflection...
Homework Statement
I just have a quick question about the delta function, I'm pretty confident in most other cases but in this simple one I'm not so sure.
$$\int_{-\infty}^{\infty} \phi (x)\delta (-x)dx$$
Homework EquationsThe Attempt at a Solution
[/B]
$$\int_{-\infty}^{\infty} \phi...
Hi.
I understand that in 1-D when E< V(minimum) there exist no physically acceptable solution to the Schrodinger Equation. I have been looking at delta potentials using Griffiths book. I follow his working for the delta potential well but when it comes to the potential barrier I don't understand...
TL;DR:
My professor asked me to graph the probability that a particle would be excited from the ground state to a stationary state with a certain energy E (y-axis) verse the energy of that new state (x-axis). I need help finding this probability as a function of E.
Probability=|<ΨE|P|Ψg>|2
P is...
Homework Statement
True/False: If a particular delta has been constructed as a suitable response to a particular epsilon challenge, then any smaller positive delta will also suffice.
Homework EquationsThe Attempt at a Solution
The submitted solution is as follows:
However, when I read this...
Thereis no proof for anything in us other than matter(and energy).
Thermodynamics works everywhere.
I think we live upto the time our system's Delta G (Gibbs free enery) remains negative.
Please friends tell me if my undrstanding is justified.
I'm trying to use the Animate function on Mathematica to show a gaussian wave packet passing through a delta potential. I'm quite new to Mathematica and this is by far the hardest thing I've had to do so please bear with me.
I effectively want to solve the integral:
##
\phi_k(x) = \left\{...
Homework Statement
I want to plot using Mathematica a wave packet entering a delta potential ##V(x) = s\delta(x) ## (s is the strength) but I need to get the physics right first and I'm having trouble with a a few parts. I need to compute the integral ## \int_{0}^{\infty} e^{-i\omega...
so, continuous signals as sums of weighted delta functions can be represented like this:
if you switch order of some variables you get ∫x(τ)δ(-τ+t)dτ, and since,I presume, Dirac delta "function" is even I can write it like this ∫x(τ)δ(-(-τ+t))dτ=∫x(τ)δ(τ-t)dτ=x(t) and we got ourselves a...
The width of Δ resonances is around 110...120 MeV.
All four of them. With modest differences. The difference in width between Δ0 and Δ++ is estimated from 5 to 9 MeV.
Why?
Δ+ and Δ0 resonances have two options to decay.
Δ+→p+π0
Δ+→n+π+
and correspondingly
Δ0→p+π-
Δ0→n+π0
In contrast, Δ++ and Δ-...
Homework Statement
\begin{equation}
\int_V (r^2 - \vec{2r} \cdot \vec{r}') \ \delta^3(\vec{r} - \vec{r}') d\tau
\end{equation}
where:
\begin{equation}
\vec{r}' = 3\hat{x} + 2\hat{y} + \hat{z}
\end{equation}
Where d $\tau$ is the volume element, and V is a solid sphere with radius 4, centered...
I've come across the equation $$\int_0^1 dx \frac{dA(x)}{dx} + B = C = \text{finite}$$ in my readings on a certain topic in physics and, in both articles i have read, the following step is taken $$\int_0^1 dx \left( \frac{dA(x)}{dx} + (B-C)\delta(1-x) \right) = \text{finite}$$
For the...
I am quite new here, and was wondering if anybody knows how this 2D integral is evaluated.
$$ \int_{-\infty}^\infty \int_{-\infty}^\infty \delta(k_1 x-k_2y)\,dx\,dy$$Any help is greatly appreciated! Thanks!
Homework Statement
Using the equations given, show that the wave function for a particle in the periodic delta function potential can be written in the form
##\psi (x) = C[\sin(kx) + e^{-iKa}\sin k(a-x)], \quad 0 \leq x \leq a##
Homework Equations
Given equations:
##\psi (x) =A\sin(kx) +...
I am looking at an explanation of the gradient operator acting on a scalar function ## \phi ##. This is what is written:
In the steps 1.112 and 1.113 it is written that ## \frac {\partial x'_k} {\partial x'_i} ## is equivalent to the Kronecker delta. It makes sense to me that if i=k, then...
Homework Statement
I am trying to show that ## \int \delta (x-a) \delta (x-c) dx = \delta (-a-c) ## via integeration by parts, but instead I am getting ##\delta (c-a) ## (or ##\delta (a-c)## depending how I go...).
Can someone please help me out where I've gone wrong: struggling to spot it...
Homework Statement
I have
##\int dx \int dy \delta (x^{2}+y^{2}-E) ## [1]
I have only seen expressions integrating over ##\delta## where the ##x## or the ##y## appear seperately as well as in the delta function and so you can just replace e.g ##y^2 = - x^{2} +E## then integrate over ##\int...
I want to calculate $$\langle x|XP|y \rangle$$ where X is the position operator and P the momentum operator, and the states are position eigenstates. But I get two different answers depending on if I insert a complete set of states.
First way:
$$\langle x|XP|y \rangle=x\langle x|P|y...
Hallo,
I have a question which elements are responsible for the increase of tangent delta in a X Capacitor and the reduction of its insulation resistance?
Hi,
I am studying transmission lines faults. There was a line that said
In case of delta star transformer in transmission line, an Earth fault on star (grounded) side is seen as a line to line fault on delta side.
There was no explanation. I tried to google solutions but couldn't find any...
The Green's function for a scalar field in Euclidean space is
$$(2\pi)^4\delta^4(p+k) \frac{1}{p^2+m^2}$$
however when I continue to Minkowski space via GMin(pMin)=GE(-i(pMin)) there's seems to be a sign error:
$$(2\pi)^4\delta^4(-i (p+k)) \frac{1}{-p^2+m^2}=(2\pi)^4\delta^4(p+k)...
My history of physics is all too rusty. Who first wrote that the work done by a conservative force is the negative of the change in potential energy? Was he/she also the one who first presented the equation?
Q's Let f,g ℝ→ℝ. Suppose that g is bounded. This means that its image is bounded or in other words there exists a positive real number B s.t. |g(x)| ≤ B ∀ x. Prove that if lim x→c f(x) = 0, then lim x→c f(x)g(x) = 0.
Work.
See the picture.
I am really confused I can't seem to understand the idea...
Homework Statement
During a .0050 second time period a rocket expels 1.000kg of gas at a velocity of 5000 m/s. Calculate the rockets average Thrust, as well as Impulse. http://imgur.com/a/uE9dVI am going to use this note for reference on a test and want to rock solid about it.
2. Homework...
Homework Statement
A wooden pallet carrying a load of 600 kg rests on a wooden floor.
(s= .28 and k= .17)
a. A forklift driver decides to push it horizontally instead of lifting it. What force must be
applied to just get the pallet moving from rest?
b. After a bit of time, the driver pushes the...