Integrals Definition and 1000 Threads

Page 35 Feynman Quantum Mechanics and Path Integrals (2-26)ψ=(iε)R I know it's a defination.But how to find some threads.How can we get this?

What I have learned in school is that differentiation and integration are opposites. By integrating a function we find the area under the graph. So, integration gives us the area. Differntiation gives slope of the function. If I am right by saying differentiation and integration are...

Homework Statement Find f'(x) for (integral from 0 to x of cos^5(t)dt)* (integral from x^2 to 1 of e^t^2 dt). No differentiation allowed in the answer Homework Equations The Attempt at a Solution. I used the product rule and integrated then differentiated the first term --> cos^5x*...

Homework Statement I'm working through Mahajan's Street-fighting Mathematics for fun, and am a bit puzzled about the following problem: The Attempt at a Solution It's mostly the first part that's tripping me up. I could use the substitution tan\theta=x and solve both integrals...

Homework Statement Well I have these three different integrals: \int{\frac{1}{\sqrt{4x^2-1}}dx} \int{\frac{1}{4-x^2}dx} \int{\frac{1}{x^2+4x+8}dx}Homework Equations Yeah well not exactly sure how to approach this... Do you use integration by substitution, where you come up with some...

Homework Statement Evaluate ∫∫F.nds where F=2yi-zj+x^2k and S is the surface of the parabolic cylinder y^2=8x in the first octant bounded by the line y=4, z=6 Homework Equations We were told that the projection is supposed to be taken in the yz plane but how?? and i have a feeling that...

Is there any clear explanation as to why exactly derivatives and integrals cancel each other [other than the integral is the anti-derivative]? To my understanding the derivative gives the slope of a curve at given point whereas the the integral finds the area under the curve. How are these...

Homework Statement Exercice 14-14, 3^{rd} edition, Spivak: Find a function f such that f^{```}(x) = \frac{1}{\sqrt{1 + sin^{2}x}}. The answer acording to the book is : f(x) = \int\left(\int\left( \int \frac{1}{\sqrt{1+sin^{2}x}} dt \right) dz...

Homework Statement Set up triple integrals for the integral of f(x,y,z)=6+4y over the region in the first octant that is bounded by the cone z=(x^2+y^2), the cylinder x^2+y^2=1 and the coordinate planes in rectangular, cylindrical, and spherical coordinates. Homework Equations...

Is there a general algebraic way to write the quotient of two definite integrals as one? I mean, what would be \frac{\int_a^b f(s) ds}{\int_c^d g(t) dt} Is it analogous to the product of integrals creating a double integral? Thanks in advance!

Hi I have a question regarding notation. I have a function f(x, y), which I would like to integrate as \int_{x>0,y<x\frac{1}{\sqrt{\pi}}+1}{f(x, y) dxdy} My question is very simple, and probably very silly: What there a notation which enables me to write the condition for the integral (x>0, y...

I made a pdf so that the equation would be more clear

Is there a formula for calculating the product of integrals, something like: \left(\int_a^b f(x) dx\right) \times \left(\int_c^d g(y) dy\right) when there is no closed-form expression for F(x) and G(y). Actually, the functions are almost identical, f(x) = x^p e^{-x} \text{ and }...

Evaluate: 1. $\displaystyle \int_0^{\displaystyle 2\pi} \frac{x \sin^{2n}(x)}{\sin^{2n}(x)+\cos^{2n}(x)}dx$, $n>0$ 2. $\displaystyle \int_0^{ \displaystyle \pi \over \displaystyle 2} \frac{x \sin x \cos x}{\sin^{4}(x)+\cos^{4}(x)}dx$

How do I solve this? How do I determine the range? Ill they be triple integrals?Please explain to me. Find the volumes in R3. 1. Find the volume U that is bounded by the cylinder surface x^2+y^2=1 and the plane surfaces z=2, x+z=1. 2. Find the volume W that is bounded by the cylindrical...

How do I solve this? How do I determine the range? Ill they be triple integrals?Please explain to me. Find the volumes in R3. 1. Find the volume U that is bounded by the cylinder surface x^2+y^2=1 and the plane surfaces z=2, x+z=1. 2. Find the volume W that is bounded by the cylindrical...

I'm trying to figure out how to integrate a data set, without knowing the function. While doing this, I got to thinking about this: If the definite integral of a function can be represented by the area under that function, bound by the x axis, then shouldn't: \int_{a}^{b}2x\frac{\mathrm{d}...

Hi, How would one go about solving equations like ∫^{b}_{a}f(s,t)g(s)ds=g(t),for f(s,t). Could we turn it into a differential equation somehow? Thanks

Homework Statement Regarding problem 1-6 in Spivak's Calculus on Manifolds: Let f and g be integrable on [a,b]. Prove that |\int_a^b fg| ≤ (\int_a^b f^2)^\frac{1}{2}(\int_a^b g^2)^\frac{1}{2}. Hint: Consider seperately the cases 0=\int_a^b (f-λg)^2 for some λ\inℝ and 0 < \int_a^b (f-λg)^2 for...

Homework Statement So I came across the integral \int^{1}_{0}x\sqrt{1-x^2} and I tried to solve it in two ways using the change of variables theorem for integration, however both ways are supposed to give me the same result, but they differ in the sign and I cannot find what I am doing...

Homework Statement My first problem is with 2ia) and 2ib), I got the correct answer, although not happy with my understanding of it. http://img826.imageshack.us/img826/1038/443pr.jpg The Attempt at a Solution (2ia and 2ib) The region that's of concern is the upper part between y = x^2 and...

In this text, I will ask a question about the power series expansion of exponential and logarithmic integrals. Now, to avoid confusion, I will first give the definitions of the two: \mathrm{Ei}(x)=\int_{-\infty}^{x}\frac{e^t}{t}dt \mathrm{Li}(x)=\int_{0}^{x}\frac{dt}{\log(t)} where Ei denotes...

Homework Statement Find the volume of the solid that lies above the cone z = root(x2 + y2) and below the sphere x2 + y2 + x2 = z. Homework Equations x2 + y2 + x2 = ρ2 The Attempt at a Solution The main issue I have with this question is finding what the boundary of integration is for ρ. I...

I have always seen the integral as the area under a curve. So for instance, if you integrated over the upper arc of a circle you would get ½\piR2. But then, I learned to do integrals in spherical coordinates and something confuses me. If you do the integral from 0 to 2\pi, you don't get the...

Homework Statement Find the mass of a solid of constant density that is bounded by the parabolic cylinder x=y2 and the planes x=z, z=0, and x=1. The Attempt at a Solution https://dl.dropbox.com/u/64325990/Photobook/Photo%202012-06-07%202%2033%2024%20PM.jpg I first drew some diagrams to...

Homework Statement A lamina occupies the region inside the circle x2+y2=2y but outside the circle x2+y2=1. Find the center of mass if the density at any point is inversely proportional to its distance from the origin. Here is the solution...

Homework Statement show that \int^{∞}_{0}\frac{sin^{2}x}{x^{2}}dx= \frac{\pi}{2} Homework Equations consider \oint_{C}\frac{1-e^{i2z}}{z^{2}}dz where C is a semi circle of radius R, about 0,0 with an indent (another semi circle) excluding 0,0. The Attempt at a Solution...

Hello again. I am hoping that someone can assist in checking my work regarding a trigonometric integral. The problem and my attempt to solve is as follows. \int\sin^{\frac{-3}{2}}(x)*cos^3(x) dx \int\sin^{\frac{-3}{2}}(x)*cos^2(x)*cos(x) dx Using a Pythagorean identity...

Homework Statement Here is the problem: http://dl.dropbox.com/u/64325990/Photobook/question.PNG Here is the answer: http://dl.dropbox.com/u/64325990/Photobook/solution.PNG So what the answer says is that you can find the volume under the surface minus the volume of the rectangle with height...

I heard that the formula below can be used to evaluate some kinds of integrals but I can't find what kinds and how to do it.Could someone name those kinds and also the procedure? \frac{d}{dx} \int_{a(x)}^{b(x)} f(x,t) dt = f(x,b(x)) b'(x) - f(x,a(x)) a'(x) + \int_{a(x)}^{b(x)}...

I'm preparing for a vector calculus course in the fall and I've been self studying some topics. I've taken multivariable calculus and I'm familiar with using double integrals, how to solve them and how to use them to find volume. From what I've read so far, I'm familiar with how to SOLVE a...

Homework Statement I'm just interested in knowing where the 4 comes from in front of the integral.

Homework Statement Do you see how y gets converted to csc? I don't get that. I would y would be converted to sin in polar coordinates.

Homework Statement do you see how the integral of r is .5? I don't get how that follows?

Homework Statement The Attempt at a Solution I understand the steps, although it took quite a while, but what I don't understand is that a triangle with base 2 and height 2, it's area is 2. With two triangles of that size the area should be 4. The books says the area is 8.

Let f : R to R be a continuous function, and suppose that definite integral from m to n |∫(m to n)f(x)dx|≤(n-m)^2 for every closed bounded interval [m, n] in R. Then is it the case that f(x) = 0 for all x in R? I tried using fundamental theorem of calculus but got stuck, since I only got that...

Homework Statement If the power of the secand is even and positive.. \int sec^{2k} x tan^{n} x dx = \int (sec^2 x)^{k-1} tan ^n x sec^2 x dx The Attempt at a Solution The way I see it, sec^{2k} x = sec^2 x dx * sec^k x dx the next step seems to be to break down sec^k, but on closer...

*SOLVED* Indefinite integrals. Arriving at different results. Mistake found. Thanks!, everything looks correct now.

Homework Statement Compute the surface integral for F = [3x^2, y^22, 0] and S being a portion of the plane r(u,v)=[u,v,2u+3v], 0≤u≤2, −1≤v≤1.The Attempt at a Solution I managed to get the correct answer, because with some luck I defined the normal in the correct direction. I am just confused...

The integral for calculating the flux of a vector field through a surface S with parametrization r(u,v) can be written as: \int\int_{D}F\bullet(r_{u}\times r_{v})dA But what's to stop one from multiplying the normal vector r_{u}\times r_{v} by a scalar, which would result in a different...

Help choose the limits of the following volume integrals: 1) V is the region bounded by the planes x=0,y=0,z=2 and the surface z=x^2 + y^2 lying the positive quadrant. I need the limits in terms of x first, then y then z AND z first, then y and then x. And also polar coordinates, x=rcost...

Homework Statement Find the area in the positive quadrant of the x-y plane bounded by the curves {x}^{2}+2\,{y}^{2}=1, {x}^{2}+2\,{y}^{2}=4, y=2\,x, y=5\,x The Attempt at a Solution This is a graph of the region: http://img21.imageshack.us/img21/2947/59763898.jpg One thing I was...

Calculate the following contour integrals using suitable parameterisations Homework Statement 1)##\oint \frac{1}{z-z_0} dz## where C is the circle ##z_0## and radius r>0 oriented CCW and ##k\ge0## 2) ##\int_c |z|^2 dz## where C is the straight line from 1+i to -1 3. Relevant equations...

Homework Statement Calculate the following contour integrals \int_{c1} (x^3-3xy^2 ) + i (3yx^2 - y^3) where c1 is th line from 0 to 1+i Homework Equations The Attempt at a Solution a earlier part of the question asked if it was analytic. using Cauchy-Reimann equations i have...

Homework Statement a) \int\int_{B}\frac{\sqrt[3]{y-x}}{1+y+x} dxdy, where B is the triangle with vertices (0, 0), (1, 0), (0, 1). b)\int\int_{B}x dxdy where B is the set, in the xy plane, limited by the cardioid ρ=1-cos(θ) The Attempt at a Solution a) Let ψ: \left\{u = y-x, v =...

Weinberg in his 1st book on QFT writes in the paragraph containing 2.5.12 that we may choose the states with standard momentum to be orthonormal. Isn't that just true because the states with any momentum are chosen to be orthonormal by the usual orthonormalization process of quantum mechanics...

Homework Statement Evaluate the follow by first changing the order of integration \int_{x=-1}^{1}\int_{y=x^2}^{2-x^2}dydxThe Attempt at a Solution This is the region we're concerned with: http://www.wolframalpha.com/input/?i=plot%28y%3Dx^2%2C+y+%3D+2+-+x^2%2C+x%3D+1%2C+x%3D+-1%29 The new...

Hi, I am able to manipulate and use double integrals, but I am having a bit of mental block when trying to visual how they actually work. First, would you agree that a double integral is simply summing a function over a region by taking lots of tiny squares (or rectangles?) of sides dx...

Homework Statement Let C be the boundary of the region bounded by the curves y=x^{2} and y=x. Assuming C is oriented counter clockwise, Use green's theorem to evaluate the following line integrals (a) \oint(6xy-y^2)dx and (b) \oint(6xy-y^2)dyHomework Equations The Attempt at a Solution...

Homework Statement Evaluate the integral Homework Equations I can substitute and thus end up with The Attempt at a Solution I then expand the denominator out and end up with 1/ However I then assume I need to factorise the top line of that fraction as this will be the...