Integral Definition and 1000 Threads

Homework Statement Let D be the triangle with vetrices ##( 0,0 ) , ( 1,0 )\mbox{ and } ( 0,1 )##. Evaluate the integral : $$\iint_D e^{\frac{y-x}{y+x}}$$ Homework EquationsThe Attempt at a Solution [/B] The answer to this problem is known (...

Homework Statement I attached an image of the multi-part problem on this post. I got correct answers to every question other than the last one. Homework EquationsThe Attempt at a Solution I believe the last part is a surface integral problem. F is given and I found n is previous parts of...

Hello. I ask for solution help from the integral below, where y and x represent angles in a metric of a spherical, 2-D surface. He was studying how to obtain the geodesic curves on the spherical surface, the sphere of radius r = 1, to simplify. The integral is the end result. It is enough, now...

Please see the attached images that reference the text. To my understanding, we wish to use the integral test to compare to a series to see if the series converges or diverges. In these two examples, we use ##\sum_{n=1}^\infty \frac{1}{n}## compared with ##\int_1^{k+1} \frac{1}{x}dx## and for...

So the classical law of force given by Newton is F= ma = dp/dt = qE. Thus if i integrate the last two equivalents I get: ∫(dp/dt)dt = q∫Edt p + C = q∫Edt correct? then what would the integral of...

Hi all, I’m having some trouble finding a minus sign in a standard calculation I have been doing. I am trying to show that if there is no enclosed current around the example loop in the enclosed jpeg, the four piecewise paths add up to zero (for the line integral part of Amp’s law). For this...

Homework Statement Use the integral test to compare the series to an appropriate improper integral, then use a comparison test to show the integral converges or diverges and conclude whether the initial series converges or diverges. ##\sum_{n=3}^\infty \frac{n^2+3}{n^{5/2}+n^2+n+1}## Homework...

Homework Statement Homework Equations The Attempt at a Solution

Homework Statement For $$f_x(x)=4x^3 ; 0 \leq x \leq 1$$ Find the PDF for $$ Y < y=x^2$$ The Attempt at a Solution So, we take the domain on x to be: $$0\leq x \leq \sqrt y$$ and integrate: $$ \int_0^{\sqrt y} f_x(x) dx = \int_0^{\sqrt y} 4x^3 dx$$ Do we integrate with respect to x or y...

Extremely quick question: According to http://mathworld.wolfram.com/PrimeNumberTheorem.html, the Riemann Hypothesis is equivalent to |Li(x)-π(x)|≤ c(√x)*ln(x) for some constant c. Am I correct that then c goes to 0 as x goes to infinity? Does any expression exist (yet) for c? Thanks.

Homework Statement The following is a problem from "Applied Complex Variables for Scientists and Engineers" It states: The following integral occurs in the quantum theory of collisions: $$I=\int_{-\infty}^{\infty} \frac {sin(t)} {t}e^{ipt} \, dt$$ where p is real. Show that $$I=\begin{cases}0 &...

Homework Statement I am computing the auto correlation and spectral density functions of the following signal: $$f(t)=Ae^{-ct}sin(\omega t)$$ $$AutoCorrelation = R_x(\tau) = \int_{-\infty}^{\infty} f(x)f(x+\tau) \cdot \frac{1}{T} dx$$ $$SpectralDensity = S_x(\omega) = \frac{1}{2\pi}...

How do I setup an integral to integrate over the following equation: V(t) = 1/(R*C) integral to t Vin(t) dt This is the capacitor voltage over time formula. I want to integrate over a sine wave from 9 to 81 degrees. Frequency of 120Hz, amplitude of 120V. The formula I used in wolframalpha is...

Homework Statement Find the following: $$ \int_0^\inf \frac{x^{a+1}e^{-x/\delta}}{\delta^{a+1}\Gamma(a+1)} dx; \, a > 1 , \delta >0 , 0 \leq x \leq \inf$$ Homework Equations - The Attempt at a Solution The numerator in the integral is constant, so it can be taken outside the integral. I then...

I'm reading Klaubers QFT book and I stuck with his derivation of Hamiltonian of scalar field on page 53. To derive it one needs to deal with integrals like this: $$\int\dot{\phi}\dot{\phi}^\dagger d^3x$$ He is using discrete plane-wave solutions and after plugging them in, we end up with...

Homework Statement a) A point charge + q is placed at the origin. By explicitly calculating the relevant line integral, determine how much external work must be done to bring another point charge + q from infinity to the point r2= aŷ ? Consider the difference between external work and work...

Homework Statement A rod of charged -Q is curved from the x-axis to angle ##\alpha##. The rod is a distance R from the origin (I will have a picture uploaded). What is the electric field of the charge in terms of it's x and y components at the origin? k is ##\frac {1} {4\pi \epsilon_0}##...

Hello. I integrated ##\sec(x) ## and got an answer. I differentiated it to verify it and it came out well. Later when I was looking in a table of integrals I saw the solution ## \ln| \sec(x) +\tan(x) | + c##. This was completely different than my solution. I do not think I made a mistake...

Homework Statement If ##\vec { F } = x \hat { i } + y \hat { j } + z \hat { k }## then find the value of ##\int \int _ { S } \vec { F } \cdot \hat { n } d s## where S is the sphere ##x ^ { 2 } + y ^ { 2 } + z ^ { 2 } = 4##. The Attempt at a Solution From gauss divergence theorem we know ##\int...

This question is about the general 1 loop correction to the propagator in QFT (this is actually not important for this question). Let's say we have an integral over an integration variable x, and this x ranges from ##-\infty## to ##\infty##. If we look at this integration contour in the complex...

Homework Statement I have a problem with this integral: ##\int_{x_0}^x \frac{dx}{\sqrt{2-2\cos{x}}}## Homework EquationsThe Attempt at a Solution I came across this while reading a book and the author says that this can be written in the form ##\int_{x_0}^x \frac{dx}{2\sin{\frac{x}{2}}}##. I...

Homework Statement Suppose that a smooth differential ##n-1##-form ##\omega## on ##\mathbb{R}^n## is ##0## outside of a ball of radius ##R##. Show that $$ \int_{\mathbb{R}^n} d\omega = 0. $$ Homework Equations [/B] $$\oint_{\partial K} \omega = \int_K d\omega$$ The Attempt at a Solution...

Homework Statement ##\int_0^{π/8}sin^2(x)cos^2(x)## Homework EquationsThe Attempt at a Solution Please see my attached work to see the train of thought. I've tried this thing about 100 times and still can't get the correct solution. I don't know if it's in the anti derivative evaluations of...

Homework Statement An electrostatic field ## \mathbf{E}## in a particular region is expressed in cylindrical coordinates ## ( r, \theta, z)## as $$ \mathbf{E} = \frac{\sin{\theta}}{r^{2}} \mathbf{e}_{r} - \frac{\cos{\theta}}{r^{2}} \mathbf{e}_{\theta} $$ Where ##\mathbf{e}_{r}##...

Homework Statement The question is; for a qunatum mechanical particle, Ψ(x) = [1/(a1/2.π1/4)].[e-(x-xo)2/2a].[eip0x/h] in here, x0, p0 and h are constants, so, Homework Equations what are the <x>; expetation value, and <P>;expectation value of momentum ? The Attempt at a Solution , [/B]...

The question is; for a qunatum mechanical particle, Ψ(x) = [1/(a1/2.π1/4)].[e-(x-xo)2/2a].[eip0x/h] in here, x0, p0 and h are constants, so, what are the <x> and <P> ?

My question is, why is the circled integral the chosen integral for this case? My thoughts are that we don't just use ##\int_0^1e^{-x}## because we need to make this two dimensional area into a three dimensional volume by doing 360 degrees of rotation. This would correspond to ##2πr##. ##2π## is...

I tried to use integration by parts. I took f(x)=arctan(x) => f'(x)= 1/x^2+1 g'(x)=cos(nx) => g(x)= sin(nx)/n So I get sin(nx)/n * arctan(x) - integral from 0 to 1 from sin(nx)/n(x^2+1) How to continue ? I'm always getting stuck with this kind of exercises ( limits of integrals ) because I don't...

Hello all, I was watching some random videos on YouTube and found one of Dr. Ben Goertzel (a leading expert in the field of AI) and he was wearing the t shirt you see below. It caught my attention. I tried working it out, but I had no luck as it got messy fast. I then tried throwing it into...

I know how to solve a differential equation using Eulers method but what if the equation has an integral part? i.e. a RLC electrical circuit. Vsource = iR + L di/dt + (1/C)int i dt can this be done? a link to how to solve this would be helpful.

Hey there, trying to figure out how to solve this integral (see picture). I've never seen an integral written in this way before. I've tried to integrate the x-part first and then the y-part and vice versa but they both gave the wrong results.

I have a few of integration equations and need to convert it into Python. The problem is when I tried to plot a graph according to the equation, some of the plot is not same with the original one. The first equation is the error probability of authentication in normal operation: cond equation...

Homework Statement Evaluate the integral: ∫csc((v-π)/2)cot((v-π)/2) Homework Equations cscx=1/sinx cot=sinx/cosx The Attempt at a Solution I first turned csc and cot into the above "relevant equations" ∫ (1/sin(##\frac{v-π}{2}##)(##\frac{sin(v-π)/2}{cos(v-π)/2}##)=∫cos-1((v-π)/2) then...

Homework Statement I have solve the integral for:to be: But I cannot figure out how to simplify the answer to the form shown above. Homework Equations The Attempt at a Solution Here is my progress so far: Any help would be appreciated

From my interpretation of this problem (image attached), the force applied to the point charge is equal and opposite to the repulsive Coulomb force that that point charge is experiencing due to the presence of the other point charge so that the point charge may be moved at a constant velocity. I...

Homework Statement Find A in p(x) = Aexp(-λ(x-a)^2) by using the equation 1 = ∫ p(x)dxHomework Equations 1 = ∫p(x)dx The Attempt at a Solution I expand the power of the exponential and then extract the constant exponential to get: Aexp(λa^2) ∫exp(-λx^2)exp(2aλx)dx I don't know how to...

Homework Statement The indefinite integral $$\int \, $$ and it's argument. The indefinite integral has a function of e.g ## \cos (x^2) \ ## or ## \ e^{tan (x)} \ ## If the argument of ## \cos (x^2) \ ## is ## \ x^2 \ ## then the argument of ## \ e^{tan(x)} \ ## is ## \ x \ ## or ## \ tan (x) \...

Homework Statement Use the integral test to determine whether $$\sum_{n=3}^{\infty} \frac{1}{n^2-4}$$ converges or diverges.The Attempt at a Solution [/B] Taking the integral we have $$\int_{}^{\infty}\frac{dn}{n^2-4}$$ Note: Mary Baos text is having us write the integrals without lower bounds...

Hi! I am trying to solve problems from previous exams to prepare for my own. In this problem I am supposed to find the improper integral by substituting one of the "elements", but I don't understand how to get from one given step to the next. Homework Statement Solve the integral by...

Homework Statement $$\int (sinx + 2cos x)^3dx$$ Homework EquationsThe Attempt at a Solution $$\int (sinx + 2cos x)^3dx$$ $$\int (sinx + 2cos x)((sinx + 2cos x)^2dx)$$ $$\int (sinx + 2cos x)(1 + 3cos^2x+2sin2x)dx$$ How to do this in simpler way?

Homework Statement Starting with the second order polarization in the time domain: (1) I am trying derive the frequency domain form: (2) Multiple sources give essentially the same formula with the same integral, I have obtained the particular ones in here from those lecture notes. My...

Homework Statement ∫∫ F ⋅ ndτ over the spherical region x^2 + y^2 + z^2 = 25 given F = r^3 r i already converted the cartesian coordinates to spherical in FHomework Equations n = r[/B]The Attempt at a Solution I know I can plug in F into the equation and then dot it with r to get the...

If I have a limit of a series then how can I convert it into integral. I know to convert a sum into an integral there must be Δx multiplied to each term and this must go zero. Can you please explain me the conversion of limit of series (normal series with no Δx) into an integral. Thank you.

Homework Statement Figure 5 shows the input and output wave forms for a proportional plus integral controller. State: (i) the controllers proportional gain (ii) the controllers integral action time The attachment below is a copy and paste of the input and output wave forms I am given...

Hi. If a function f is normalizable ,ie f→0 as | x | → infinity or r→ infinity then I presume the following surface integral f dS over infinite space is zero ? But I thought about this again and it seems like a case of zero x infinity. The function is zero at the infinite surface but the area...

Homework Statement (Scroll to bottom for the true question) Suppose we are to find the integral from -∞ to +∞ of (let’s just say) e-x2dx Homework Equations ∫∫f(x)g(y)dxdy = (∫f(x)dx)(∫g(y)dy) The Attempt at a Solution We can square the integral we want to solve for then use my relevant...

Homework Statement For a vector field $$\begin{equation} X:=y\frac{\partial{}}{\partial{x}} + x\frac{\partial{}}{\partial{y}} \end{equation}$$ Find it's integral curves and the curve that intersects point $$p = \left(1, 0 \right).$$ Show that $$X(x,y)$$ is tangent to the family of curves: $$x^2...

Homework Statement Hello, I´ve added an image where the task is shown. I am wondering about the integral bounds here. When doing the substitution, shouldn't the bounds be inf and 0? When using that u = ln x, i.e. u(0) =inf, u(1) = 0. Homework EquationsThe Attempt at a Solution

Consider ##X## and ##Y## two vector fields on ##M ##. Fix ##x## a point in ##M## , and consider the integral curve of ##X## passing through ##x## . This integral curve is given by the local flow of ##X## , denoted ##\phi _ { t } ( p ) .## Now consider $$t \mapsto a _ { t } \left( \phi _ { t } (...

I am looking for good references / clarifications on the subject. First of all, my question is concerned only with mathematical formulation of something that sort of plays the role of the Feynman path integral of the "standard" QFT. It is not concerned with the physical or philosophical...