Integrals Definition and 1000 Threads

Hi I have an integral over [0,1] of product of two matrices say A(t). B(t) and I wish to bound its norm. Can you say that ||integral (AB)||<||B(t)||.||integral (A)|. is there some conditions on that to occur thanks sarrah

Homework Statement Find the Integrals of \frac{x^2}{e^x+1}\\ \frac{x^3}{e^x+1} Homework Equations Integration by parts The Attempt at a Solution I did IBP twice and it seemed to just get bigger and uglier and now I am stuck. I found the solutions online of the integrals but...

Suppose we are given two functions: f:\mathbb R \times \mathbb C \rightarrow\mathbb C g:\mathbb R \times \mathbb C \rightarrow\mathbb C and the equation relating the Stieltjes Integrals \int_a^\infty f(x,z)d\sigma(x)=\int_a^\infty g(x,z)d\rho(x) where a is some real number, the...

Hello, I've been reviewing some calculus material lately and I just have a couple questions: 1) I've seen infinite series shown graphically as a collection of rectangular elements under a curve representing an approximation of the area under the curve. But the outputs of the infinite...

Hello. Question is attached. Can someone check my answer? Did I convert the last part correctly? Is everything correct?

Hey! How do I integrate ∫tln√(t+1) and ∫4te^(2-0,3t)? Thanks in advance.

Initially, the purpose of this tutorial will be to explore and evaluate various lower order derivatives of the Hurwitz Zeta function. In each case, the Hurwitz Zeta function will be differentiated with respect to its first parameter. A little later on - although this will take some time! - these...

Hello! I found the following problem on AOPS: Which is larger, $$\Large \frac{\int_{0}^{\frac{\pi}{2}}x^{2014}\sin^{2014}x\ dx}{\int_{0}^{\frac{\pi}{2}}x^{2013}\sin^{2013}x\ dx}\ \text{or}\ \frac{\int_{0}^{\frac{\pi}{2}}x^{2011}\sin^{2011}x\ dx}{\int_{0}^{\frac{\pi}{2}}x^{2012}\sin^{2012}x\...

Given a sphere x^2 + y^2 + z^2 = a^2 how would I derive the surface area by using surface integrals? The method I've tried is as follows: dA = sec\ \gamma \ dxdy where gamma is the angle between the tangent plane at dA and the xy plane. sec \gamma = \frac{|\nabla \varphi|}{\partial \varphi...

http://d.kankan3d.com/file/data/bcs/2014/0508/w65h1446064_1399517186_873.jpg 1.How to deal with the delta functions in eq.2.3.153 to obtain the eq.2.3.154 by integrating over q'? 2.How to caculate the integral from eq.2.3.154 to eq.2.3.156, especially the theta function?

trigonometric integrals; choosing which one to "break up?" When you have two different trigonometric functions multiplied together within the integral, for example integral of (cos^4*sin^6) how do you tell which one to "break them up" to substitute an identity in? Thank you!

Homework Statement ∫∫Rarctan(y/x) dA, where R={(x,y) | 1\leqx2+y2\leq4, 0\leqy\leqx Homework Equations x=rcos(θ) y=rsin(θ) x2+y2=r2 The Attempt at a Solution I know that the range of r is 1 to 2 but I can't figure out how to change the second part into θ. If I change y and x to...

Integrals containing \frac{1}{\sqrt{x^2+a^2-2xa \cos{\theta}}} occur frequently in physics but I still have problem solving them. Is there a general method for dealing with them?(Either w.r.t. x or \theta ) Thanks

I do not know how to formulate formulas on this forum so I just wrote it neatly on a piece of paper and linked it. http://puu.sh/8fwXr.jpg Thankss.

Hello I am trying to solve this integral 25-9x^2-25y^2/9 dydx integrating from 0 to sqrt(9-9x^2/25) and the limits of the second integration are 0 to 5. I can find tutorials on how to find the definite double integral of a single variable, but not for two variables. Any clues? edit: so far...

Hey! It is the first time I post on this subform. Please forgive me if I do something wrong. Homework Statement F(x)=\int^x_0f(t)dt for R \in t \rightarrow f(t) Homework Equations Is it true that 0 \leq f(x)\leq 3 for 0<x<1 \int^x_0 tf(t)dt \leq x^2 for all x \in (0, 1)? "The Attempt at...

\int \frac{d}{dx}f(x)dx = f(x) + C_x \iint \frac{d^2}{dx^2}f(x)dx^2 = f(x) + xC_x + C_{xx} \int \frac{\partial}{\partial x}f(x,y)dx = f(x,y) + g_x(y) \int \frac{\partial}{\partial y}f(x,y)dy = f(x,y) + g_y(x) \iint \frac{\partial^2}{\partial x^2}f(x,y)dx^2 = f(x,y) + x g_{x}(y) + g_{xx}(y)...

Homework Statement It is given that integral(1 to 2) g(x)dx=22 integral (1 to 4) g(x)dx=7 integral (1 to 16) g(x)dx=13 Find integral (4 to 16) Homework Equations Using properties of integrals, integral(4 to 16)= integral(1 to 16) - integral(1 to 4) The Attempt at a...

Homework Statement After successfully solving a lot of integrals I gathered 4 ugly ones that I can not solve: a) ## \int _{-\infty} ^\infty \frac{cos(2x)}{x^4+1}dx## b) ##\int _0 ^\infty \frac{dx}{1+x^3}## c) ##\int _0 ^\infty \frac{x^2+1}{x^4+1}dx## d) ##\int _0 ^{2\pi } \frac{d\varphi...

Homework Statement Find the area of the part of the sphere x^2 + y^2 + z^2 = 4z that lies inside the paraboloid x^2 + y^2 = z Homework Equations The Attempt at a Solution I solved for the intercepts and found that they are z=0 and z=3. The sphere is centered two units in the z-direction above...

Homework Statement Calculate following integrals: a) ##\int _{|z|=1}\frac{e^z}{z^3}dz## b) ##\int _{|z|=1}\frac{sin^6(z)dz}{(z-\pi /6)^3}## Homework Equations The Attempt at a Solution I am really confused, so before writing my solutions I would need somebody to please tell me: - What is...

Typical introductions to path integrals start with asking for the value of \langle x_1,t_1 | x_2,t_2 \rangle. This is usually interpreted as the probability amplitude of observing a particle at x_2 at time time t_2 given that it is located at x_1 at t_1. But is this so? I am having trouble...

Homework Statement I often have a problem dealing with unknown functions in derivations. Recently I was looking at variance of pdf's and tried to do the integral below with no success. Could someone suggest a method, or point out where I am going wrong. Homework Equations Show ∫(x - μ)2...

Homework Statement Calculate real integrals using complex analysis a) ##\int_{-\infty}^{\infty}\frac{dx}{x^2+1}## b) ##\int_0^\infty \frac{sin(x)}{x}dx##Homework Equations The Attempt at a Solution a) ##\int_{-\infty }^{\infty }\frac{dz}{z^2+1}=\int_{-R}^{R}\frac{dx}{x^2+1}+\int...

I have these integrals to find: ∫ (5x^2 + sqrt(x) - 4/x^2) dx ∫ [cos(x/2) - sin(3x/2)] dx ∫ s/sqrt(s^2 + 4) ds (upper coordinate is 5 lower coordinate is 1) I have worked it out as: ∫〖(5x^2+√x〗-4/x^2) dx=5x^3/(2+1)+x^(1/2+1)/(1+1/2)-4x^(-2+1)/(-2+1)+C=5/3 x^3+2/3x^(3/2)+4/x+C...

hey pf! i had a question. namely, in the continuity equation we see that \frac{\partial}{\partial t}\iiint_V \rho dV = -\iint_{S} \rho \vec{v} \cdot d\vec{S} and we may use the divergence theorem to have: \frac{\partial}{\partial t}\iiint_V \rho dV = -\iiint_{V} \nabla \cdot \big( \rho...

The true FTC for surface integrals Let's say that ##\vec{f}## is an exact one-form, so we have that ##\vec{f}=\vec{\nabla}f##, and ##\vec{F}## is an exact two-form, so we have that ##\vec{F}=\vec{\nabla}\times \vec{f}##. The fundamental theorem of calculus for line integral says that...

Could someone help me with these two problems? I've been at them for an hour, but have very little clue how to go about solving either of them. Homework Statement 1)∫ 6 csc^3 (x) cot x dx Homework Equations The Attempt at a Solution 6 ∫ csc^3 (x) dx) / tan x csc^3 / tan x =...

Homework Statement Using Washer Method: Revolve region R bounded by y=x^2 and y=x^.5 about y=-3 Homework Equations V= integral of A(x) from a to b with respect to a variable "x" A(x)=pi*radius^2 The Attempt at a Solution pi(integral of (x^.5-3)^2 -(x^2)^2-3) from 0 to 1 with...

Homework Statement (a) Find the Fourier transform f(ω) of: f(x) = cos(x) between -pi/2 and pi/2 (b) Find the Fourier transform g(ω) of: g(x) = sin(x) between = -pi/2 and pi/2 (c) Without doing any integration, determine f(ω)/g(ω) and explain why it is so Homework Equations f(ω) =...

Indefinite integrals with different solutions? Homework Statement \int \csc ^{2}2x\cot 2x\: dx Solve without substitution using pattern recognition Homework Equations As above The Attempt at a Solution To try a function that, when differentiated, is of the same form as the...

By FTC, every function f(x) can be expessed like: f(x) = \int_{x_0}^{x}f'(u)du + f(x_0) Now, I ask: f(x) is a antiderivative of f'(x) or is a family of antiderivative of f'(x) ?

Hello, and thank you in advanced for this. I am having trouble with setting up most if not all of my integrals when I am trying to find the elements of an inertia tensor. What would I do if i need to find say the tensor for a disk, but i don't know what to take for my three limits to be. i get...

Homework Statement \int_{-\infty}^{+\infty} e^{-\left|x\right|} \,dx The Attempt at a Solution So I know you are supposed to split this integral up into two different ones, from (b to 0) and (0 to a) where b is approaching - infinity, and a is approaching +infinity, but how would I take...

Hello I am in pre-calculus which is the next math class after algebra 2 and there are many scientific equations that require a knowledge of calculus to solve. For example I do science olympiad maglev and many of the equations to solve for magnetic flux or magnetic fields etc.. use derivatives...

in understand why we write the dx in riemann integral , but in the indefinite integral why do we use that ? what is the relation between the area under a curve , and the antiderivative of that of that curve ??

Today I tried to show that rotational kinetic energy was equivalent to standard translational kinetic energy. So I started with kinetic energy, T = ∫dT. Then, because T=1/2mv^2, I substituted dT=1/2v^2dm and then because m=ρV, I substituted dm=ρdV. Then, after substituting v=ωr, I got the...

Homework Statement Find the volume of the solid bounded above by the surface z = x^2 + y^2 and below by the triangular region in the xy-plane enclosed by the lines x = 0 , y = x , and x + y = 8. Homework Equations V = ∫∫ Height Base The Attempt at a Solution I first found...

What are the real life applications of improper integrals? Why are they on the syllabus of every first course in calculus? I am looking for examples which have a real impact.

Calculating residues are useful when we are trying to solve some improper integral, because the Cauchy principal value will be the sum of residues inside the path taken (if the integral along the complex path tends towards 0). When we have a proper integral of trigonometric functions, this is...

Homework Statement What is the integral from negative infinity to positive infinity of the following functions? a) f(z) = \frac{e^{-i5z}}{z^{2}+1} b) f(z) = \frac{e^{-i5z}}{z^{2}-1} c) f(z) = \frac{1}{π}\frac{a}{z^{2}+a^{2}} d) f(z) = e^{\frac{-(z-ia)^{2}}{2}} e) f(z) = \frac{sinz}{z}...

A question about an integral encountered in a paper I am reading about Green's Functions of the acoustic wave equation ... The integral encountered: Im{Integrate[ exp((i*y-a)*k), dk, 0, Infinity]} = Re{1/(y+ i*a)} where i = sqrt(-1) and a,y,k elements of R. Been a while since I've calculated...

I am having a difficult time finding the parametric equations x = x(t) and y = y(t) for line integrals. I know how to find them when dealing with circles, but when it comes to finding them for anything else, I don't see the method...it all seems very random. I did fine with finding the...

Okay, I am trying to determine the Fourier transform of cos (2\pix)=f(x) Where F(k)=^{\infty}_{\infty}\intf(x)exp^{-ikx} dx, So I use eulers relation to express the exponential term in terms of cos and sin, and then I want to use sin/cos multiplication integral results, such as...

Hello, I have this integral here: \[\int e^{\sqrt{x}}dx\] and I wanted to ask, why can't I treat it like I would treat this integral: \[\int (3x+5)^{5}dx\] In which I would integrate as if g(x)=3x+5 is a normal x, and then divide by the inner derivative ? I tried it with the upper integral...

Homework Statement Experiments show that a steady current I in a long wire produces a magnetic field B that is tangent to any circle in the plane perpendicular to the wire and whose center is the axis of the wire. Ampere's Law relates the electric current to its magnetic effects and states...

Homework Statement integral of 1/sqrt(9-x^2) from 0 to 3 Homework Equations /// The Attempt at a Solution I integrate it correct to arcsin(x/3) from 0 to 3 Get the correct anwser of pi/2. But there is another question, At which value of x in the integration region [0,3]...

Homework Statement Which technique i should use to solve these integrals? Homework Equations The Attempt at a Solution

I do not understand how I would do this with long division since there is only 2 terms. I can't remember the trick. Here is what I have so far. $$ \int \frac{3x^2 - 2}{x^2 - 2x - 8} dx$$ so I got $$\int 3 + \frac{x^2 - 2}{(x - 4)(x + 2)}$$ I'm not sure if that's right? I just factored it out...

Homework Statement \int (x-2)-3/2dx Homework Equations \intf(x)dx from 0 to ∞ = lim (t\rightarrow∞) \intf(x)dx from 0 to tThe Attempt at a Solution I have the solution from the solution manual, but I'm just not sure on one of the steps, after you substitute u=(x-2) and du=dx, then integrate...