parts Definition and 838 Threads

Hello. I'm attempting to integrat ∫ln(x+x^2)dx Our professor gave us the hint of x(1+x) I believe u= ln(x+x^2) and du=1+2x/x+x^2 I am not sure what dv should be Any help would be greatly appreciated! Thanks

Homework Statement Hi, I'm doing fouier transforms and I'm not sure how to integrate (2-x)cos(nPi/2)x, (1,2). Anyone able to help me out? Even the indefinite integral would be fine. Homework Equations The Attempt at a Solution I guess u would be (2-x) and dv would be cos(nPi/2)x dx. I'm not...

Hi guys, I'm having a bit of trouble splitting the RHS of the following expression into real and imaginary parts: (χ'+iχ")/A = \frac{1}{ω-ω_{0}-iγ/2} (It's to find expressions for absorption coefficient and index of refraction, but that's irrelevant). I've defined a = ω-ω_{0} and b =...

Substitution method with Integration by Parts? Homework Statement Evaluate the integral... ∫x^3[e^(-x^2)]dx Homework Equations ∫udv=uv-∫vdu The Attempt at a Solution I first tried using integration by parts setting u and dv equal to anything and everything. This seemed to make...

Hi, I am working on a design that has a stack of CSK PC/104 pcb boards fastened togther using HEX spacers. One of the PCB boards is being designed by an different design team. They have already manufactured their board but it turns out that the screw holes for the Hex spacers are...

∫xax u=x du=dx dv=axdx v=ax/lna = xax - ∫axdx/lna is my solution right? my problem now is how to integrate the expression xax - ∫axdx/lna please help..

me and my father are working on a new project for his company and we need a supplier which has a big variety of parts and sells for low quantities. i will be glad if anyone can recommend me on good suppliers =>

Homework Statement Calculate the following integral exactly (no approximations) by the method of integration by parts: ∫0t SinIntegral[x] dx Homework Equations the following hints are given: D[SinIntegral[x], x] = Sinc[x]; and SinIntegral[0] = 0 The Attempt at a Solution...

e-z2 where z is a complex number a+ib

Hi, I wonder if anyone knows when (maybe always?) it is true that, where z=x+iy \text{ and } f : \mathbb{C} \to \mathbb{C} \text{ is expressed as } f=u+iv, \text{ that } f'(z)=\frac{\partial u}{\partial x}+i\frac{\partial v}{\partial x}? I'm pretty sure that this is true for f=exp. I...

Circuit schematics for "standard" parts Hi, I graduated from computer engineering, but I want to learn more about circuits. I did get the chance to play with Quartus 2 in some of my courses and I was wondering if there is a place where I can learn about the circuit schematics for the most...

Homework Statement I have set myself the problem of modeling a KER's technology applied to road cars. I am looking to establish the kinetic energy of a vehicle corresponding to a specific drive cycle for instance the NEDC or similar. I have distance speed and time data for the drive...

Homework Statement Use integration by parts to derive the formula: \int (a^2 - x^2)^n dx = \frac{x(a^2-x^2)^n}{2n+1} + \frac{2a^2n}{2n+1}\int \frac{(a^2 - x^2)^n}{(a^2 - x^2)} dx + C Homework Equations Integration by parts general formula ∫udv = uv - ∫vdu The Attempt at a...

Homework Statement Part A: Mass of Mg (s) = 0.31 g Initial temperature of calorimeter contents = 24.1 C Finial temperature of calorimeter contents = 36.8 C Part B: Mass of MgO (S) = 1.22 g Initial temperature of calorimeter contents = 24.0 C Finial temperature of calorimeter contents = 31. 9 C...

Homework Statement Show that the real and imaginary parts of the wavenumber, k, are given by k(real)=[sqrt(epsilon(real))]omega/c and k(imaginary)=[epsilon(imaginary) *omega/(2c sqrt(espilon(real))) The Attempt at a Solution k^2= mu epsilon omega^2 (1+(i g/epsilon*omega)) k^2...

Homework Statement This was done on my Physics II class, ans the Professor has'nt want to explain it to usA 2 Circular Metallic Plate Capacitor, maybe of a diameter of 15cm, was connected to a constant sourch of DC voltage until it was charge to 10Volt, after this the source was DISCONNECTED...

Is there a way within reasonable errors to say what part of the positive integers are prime and what part is factored greater than one? Oh course one is a factor of all numbers greater than zero. Yeats ago playing around a floating constant became known to me. to the tenth decimal place is...

Homework Statement ∫r^3/(4+r^2)^(1/2) dr Homework Equations ∫udv=uv-∫vdu The Attempt at a Solution I know that integration by parts must be used. I tried doing it with 4+r^2 as u, but kept running into issues..then I got an answer but it appears to be wrong. I guess I am not sure...

Hi, I'm wondering how to integrate 4xe^(4x). I got: 4[1/4xe^(4x)-1/16e^(4x)+c] ? which reduces to xe^(4x)-1/4e^(4x)+c Is this the correct integral? Thanks.

Homework Statement Solve integral \int^{1}_0(1-x)\frac{d}{dx}\frac{\sin Cx}{C}dx Homework Equations \int udv=uv-\int vdu The Attempt at a Solution u=1-x dv=\frac{d}{dx}\frac{\sin Cx}{C}dx What is v? How to integrate \frac{d}{dx}\frac{\sin Cx}{C}dx?

Homework Statement I am doing self-study. I am on problem 5.6 #27 in the Stewart text 3rd E. I don't understand why the integration limits changed after the given substitution. The given substitution was: x=θ^2 dx=2θdθ Homework Equations Please see attachment. The Attempt at...

Hello all! So if I wanted to make and order a part to a device I am designing, where would I go to do that? I know this may seem like a weird question but here is my situation. My brother has two graphics cards in his computer and there is a VERY thin space between them, and because of that...

Homework Statement \int_0^\infty{ \frac{1}{x} e^{-x}} Homework Equations Integration by parts \int{u dv} = uv - \int{v du} The Attempt at a Solution u = \frac{1}{x} du = \frac{1}{x^2} dx v = -e^{-x} dv = e^{-x} dx -\frac{1}{x} e^{-x} - \int_0^\infty{-e^{-x}...

Homework Statement Hello, I am supposed to express the and the phase part of expression: \displaystyle{S=\frac{k}{\sqrt{1+i\gamma_0}} \cdot exp\left(\frac{z}{1 + i\gamma_0}\right)} Homework Equations The answer should be in the form: \displaystyle{S=a(\gamma_0) \cdot...

Homework Statement Find four complex numbers z each with the property that Re(z), Im(z), Re(z-1), Im(z-1) are all integers, where Re and I am denote the real and imaginary parts respectively of a complex number. Homework Equations Maybe 1/z = \frac{\bar{z}}{|z|2} ? On my screen that code...

Homework Statement integrate: r2*exp(i*k*r - r2/a2) from -infinity to +infinity (in terms of r) Homework Equations relevant integration table The Attempt at a Solution not sure what this function or the method to solve this function is called

I'm watching the video series on Quantum Mechanics taught by Leonard Susskind, (from Stanford). On Lecture #3, Dr. Susskind says that integration by parts is: ∫FG' = -∫GF' However from what I know integral by parts to be, there i missing a +FG on the righthand side, or something... since I...

Hello, thanks for reading. This is a general question: as far as I know, integration by parts is allowed only with functions that are continuously differential. However, I'm reading Griffiths Quantum book, and he easily uses this technique in integrals involving the delta "function" and the...

Hello, I am looking for something to keep plastic parts warm and pliable. We have plastic discs that need metal pins snapped into some grooves and they snap wayyy to tight. We checked with a vendor and the material is still within spec, but I cannot change the material It takes one minute...

According to Wikipedia in the progressive era the classics were removed from education. I know this isn’t completely true (At least world wide) because I learned a small amount of Greek Mythology (I live in Canada) in school. However, there was no study of Plato or any amount of philosophy at...

Homework Statement The question is what has gone wrong in this proof, it is worth noting this a definite integral between pi/6 and pi/4: ∫ tan(x) dx = ∫ sin(x)/cos(x) dx Let u = 1/cos(x) and dv = sin(x) dx So du= sec(x)tan(x) and v = -cos(x) When we substitute back in we get: ∫ tan(x)...

Homework Statement S P^4 e^-P DP Homework Equations My parts. The Attempt at a Solution I know you can do u = P^4, and DV = e^-P Then, you get du = 4P^3 dx and V = -e^-P -P^4 e^P + S 4P^3 e^-p dx Now, I can just repeat that for the intergral until I get to were the P...

Homework Statement For ordinary 1D diffusion show that the mean value of the square of the position is equal to 2Dt Homework Equations \left\langle {x^2 \left( t \right)} \right\rangle \equiv \int\limits_0^\infty {x^2 p\left( {x,t} \right)dx} \frac{\partial }{{\partial t}}p\left(...

Homework Statement ∫▒〖(2x-1)e^(-x) 〗 dx I don't want to butcher this but I know you use integration by parts, I just don't know how to do this one in particular because i is one of the simple ones I was told. Please Help

Homework Statement problem: \int2arctanx dx 2\intarctan dx u=arctanx du=1/(1+x2) v=x dv=dx xarctanx-\intx/(1+x2) integrate by parts a second time... u=x du=dx v=arctanx dv=1/1+x2 xarctanx-\intarctanx My final answer I get it 2xarctanx-2xarctanx+2/x2+1 which is...

What is the difference? I was pretty bored last night so I got onto Yahoo Answers and answered a few calculus questions. It was a simple integration by parts question: \intxsin(x) dx I solved as: u = x du = dx dv = sin(x) dx v = -cos(x) uv - \intvdu -xcos(x) + \intcos(x)dx =...

Can you please tell me how to integrate by parts the d'alembertian of a 4-variable function over a volume dx * dy * dz * dt. I have stumbled upon this seemnigly simple exercise on my way to understanding QFT of scalar fields.

Here I used integration by parts to try to solve an integral (I got it wrong, it seems), I know this has no "simple" solution, but, can anyone explain me exactly what did I do wrong? Here is what I did...

Some say that there are parts but their properties depend on the whole. But if we cannot assign properties to the 'parts' of an entangled system, what can it be to be a 'part' or any kind of entity in the first place? Can we say that there are parts but that they are not independent? What can...

I'm sure many of you are aware of CVTs or continuously variable transmissions. Many of you are also aware, I am sure, of off-the-shelf gearboxes which you can use to step up/down (typically) the output of a motor. Do they have a device which allows a variable gear ratio, especially one...

Homework Statement Hi There is a step in my book, which I can't follow. It is the following \int_0^1 {w\left( {\frac{{d^2 u}}{{dx^2 }} - u + x} \right)dx} = \int_0^1 {\left( { - \frac{{dw}}{{dx}}\frac{{du}}{{dx}} - wu + xw} \right)dx} + \left[ {w\frac{{du}}{{dx}}} \right]_0^1 I...

Homework Statement Find the solution to: y' = x.y.cos(x^2)Homework Equations Integration by Parts method.The Attempt at a Solution Step 1 (dy/dx).(1/y) = x.cos(x2) (1/y) dy = x.cos(x2) dx Step 2 Integrate both sides. ln|y| = integratal of [ x.cos(x2) dx ] Step 3 Using integration by...

Somebody could explain me, how of the second line arrive to the third one? in my book says that is integration by parts, please helpppp :eek:

The attempt at a solution \begin{equation*} \begin{split} \ -\ i\int\psi^* \frac{\partial{\psi}}{\partial x}= \\ -i(\psi^*\psi\ - \int\psi \frac{\partial\psi^*}{\partial x})\space\ (?) \end{split} \end{equation*} I thought \psi^*\psi\ = \ constant\neq\ 0. However, it vanishes in...

Parts Produced Vs Total Downtime - Graphical Interpretation Hi all! I'm working on a project analyzing downtime for a manufacturing floor. The department makes between 6 and 8 millions parts per month with 10-18 thousand minutes of unplanned downtime collectively (changeovers, maintenance...

Is there a simple way to see how all the spin and orbital angular momentum of a protons parts (quarks and gluons) sum precisely to that of a spin 1/2 fermion? Thanks for any help!

Hi all, I have this expression containing complex numbers and I wanted the expression to be displayed with real parts only. How can i do this? For instance, the original expression is, eqn = (16.0001+3.16141*10^-21 i)-(0.00860351-1.16927*10^-18 i) Ao[1]+(0.00537811-4.47536*10^-19 i)...

I'm just curious about the proofs of Integration by Parts & the Change of Variables formula as given in this book on page 357. I think there are a lot of typo's so I've uploaded my rewrite of them but I am unsure of how correct my rewrites are. If someone could point out the errors & why I...

Basically I have answered a question using the integration by parts formulae to work out the centre of gravity inside a fan blade using :- v.du/dx = v.u - u. dv/dx with the integral limits of 0 ==> 20 when v = x then dv/dx =1 when du/dx = 0.3 sinx then u = 0.3cos x and sub this into...

Homework Statement Take the integral of the following: 1. ln(2x+1) 2. arctan4x 3. ecosxsin2x evaluated from 0 to pi The Attempt at a Solution 1. took the derivative of ln(2x+1) and integrated dx. my solution was: xln(2x +1) + x + [(2x + 1)-2]/2 + C The books answer was...