What is parts: Definition and 838 Discussions

In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement. Commonly used are parts-per-million (ppm, 10−6), parts-per-billion (ppb, 10−9), parts-per-trillion (ppt, 10−12) and parts-per-quadrillion (ppq, 10−15). This notation is not part of the International System of Units (SI) system and its meaning is ambiguous.

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  1. B

    Easy integration by parts but getting wrong answer. Help

    Homework Statement I am actually looking for the expectation of x for the wavefunction that is \Psi (x) = \sqrt{\frac{2}{L}}Sin(\frac{\pi x}{L}) for 0 < x < L. To do this I need to find the solution to this integral: f = \int_0 ^L \! \Psi^* x \Psi \, dx = \int_0^L \...
  2. P

    Creative integration by parts

    "Creative" integration by parts Homework Statement Evaluate I=\int_{0}^{Inf}e^{-kw^{2}t}cos(wx)dw in the following way. Determine (partial derivative) dI/dx, then integrate by parts. Homework Equations \int udV = uv - \int vdU The Attempt at a Solution So I have to figure out...
  3. M

    SHM Math Explodes (Req: help finding Real parts)

    Homework Statement I'm not attempting a specific problem, I'm just trying to find a correct way of doing the math behind simple harmonic motion ODEs... The example problem I've given myself (based on the books I'm using) is a dashpot with constant c, spring with constant k and a mass m...
  4. I

    Integration by parts, how to find int 1/(x (ln 3)^2) dx

    Homework Statement int dx / (x (ln 3)^3) can someone tell me how to start this problem what's my u and dv ??
  5. K

    Calculus Simple Integration by Parts question

    1. The problem is this: The antiderivative from 0 to 1 of (e^x)*sin(Nx)dx I tried integrating by parts several times and I'm just not sure if what I'm doing was correct. I keep hitting a dead end. I'm not sure if I'm supposed to IBP twice or substitute sin(Nx) for something else. Help...
  6. C

    Integration by Parts: Solving Homework

    Homework Statement \int(sin(x)^{-1}), dx Homework Equations *By Parts Formula: f(x)g(x) - \int(g(x) f'(x)) dx Also for d/dx sin(x)^{-1} I used 1/sqrt(1-x^{2}) The Attempt at a Solution Just started learning this method, I tried letting f(x) = sin(x)^{-1} and g(x) = dx but nothing really...
  7. N

    Custom parts and Custom Hydraulic Arms?

    I am building a custom trailer, that will have "cages" ranging in size from 20" tall by 40" wide by 6' long to 39" tall, 40" wide, 8' long. And stacked up to 6 high and 2 wide. Now with my questions. I want to be able to open or unfold the cages kinda like a fishing tackle box out sideways of...
  8. F

    I don't understand integration by parts

    Hello everyone Let's say I want to do this integral: \int_{}^{}f(x)g(x)\,dx We use this formula \int f(x)g'(x)\, dx=f(x)g(x)-\int f'(x)g(x)\, dx I don't understand the utility of this equation, since we want to find \int_{}^{}f(x)g(x)\,dx and not \int f(x)g'(x)\, dx Please...
  9. B

    Integration by parts MIDTERM really quick question

    integration by parts! MIDTERM...really quick question...please help! Homework Statement \int arctan4t dt Homework Equations The Attempt at a Solution ive been attempting this all day. the answer is t arctan4t-1/8 ln(1+16t^2)+C i get this asnwer up until the 1/8... a...
  10. B

    Integration by parts MIDTERM really quick question

    integration by parts! MIDTERM...really quick question...please help! Homework Statement Evaluate the two following integrals: \int xcos5x dx and \int ln(2x+1) dx Homework Equations The Attempt at a Solution ok, for the first one, the answer is 1/5 x sin5x +...
  11. M

    Decomposition of a R.V. into dependent and independent parts

    Given random variables X and Y, which are not independent, is it always possible to find a random variable W which is independent from X, such that Y = f(X,W), for some function f? Example: let the joint distribution of X and Y be Y 0 1 X+------- 0|1/3 1/6 1|1/6 1/3 Then if we...
  12. F

    Integration by Parts Help

    Homework Statement \int x*(ln(x))^4dx = 4ln|x|^3-12ln|x| Homework Equations The Attempt at a Solution I did chart method u...dv...+/- ------------------------ x...ln|x|^4...+ 1...(4ln|x|^3)/x.. - 0...12ln|x|...+ ......-
  13. D

    Integrating Arc Functions: \intx*arctg(1/x)dx

    \intx*arctg(1/x)dx i have such problems integrating arc functions, don't know why, but they never turn out right,, by using \intudv=uv-\intvdu u=x du=dx dv=arctg(1/x) v=[1/(1+(1/x)2)]*ln|x| =[x2/1+x2]ln|x| \intx*arctg(1/x)dx=x*arctg(1/x)-\int(x3ln|x|)/(x2+1)dx now...
  14. K

    Haven't been taught integration by parts yet

    http://usera.ImageCave.com/kamranonline/369529f005b9d646328ba8de471139.gif Attempt to the solution. I took u=\sqrt{t} and from there i went upto : 2\intu^2Sin(u^{2})dx dunno wat to do next. Havn't been taught integration by parts yet.
  15. T

    The Mystery of Computer Parts Doubling in 18 Months

    how come some computer parts double they're power once in like 18 months or so? it's kind of weird...alwais +100% and in 18 months or so...for example take the RAM memory...they came like this(in MB): 8,16,32,64,128,256,512,1024,2048,4096,8192! I didn't cheked,but the 16 GB RAM stick might be...
  16. wolram

    Dark Energy & Dark Matter: Parts I & II by Barak & Leibowitz

    arXiv:0812.4561 [pdf] Title: On Dark Energy and Dark Matter (Part I) Authors: Shlomo Barak, Elia M Leibowitz Comments: 12 pages, 1 figure Subjects: Astrophysics (astro-ph) 2. arXiv:0810.4034 [pdf] Title: On Dark Energy and Dark Matter (Part II) Authors: Shlomo Barak, Elia M...
  17. N

    Integrating ln(x+1) with Integration by Parts

    Homework Statement integrate ln(x+1) dx (integrate by part) Homework Equations integrate e^-2x sin3x dx The Attempt at a Solution 1st,i make u=x+1 ,so du/dx =1 du=dx..while i use /dv =/ln(x+1) dx and after integrating my v=1/(x+1) so subtitute into uv -/vdu but my ans turn out to...
  18. I

    Can you sum the parts within ten seconds?

    I asked this of my maths lecturer in uni. He took about ten seconds to mentally perform the calculation/integration. Can you beat his time? Q. A cyclist rides 100 miles from point A to point B at a constant velocity of 20mph. As he leaves point A, a bee on his handlebars flies ahead of him...
  19. Z

    Integration by parts and fourier series

    hello, i'm a self learner currently learning Fourier series. Anyway, I'm having some problem with a question regarding the inner product of two complex functions. This is defined by an integral from negative infi to positive infi of the multiplication of one function and the complex...
  20. 2

    Domain and Evaluation of Double Integral with Integration by Parts

    Homework Statement How can i find the integral of \int e^{-x^{3}}dx Homework Equations The Attempt at a Solution I tried using integration by parts, but it doesn't seem to give a nice way to solve either.
  21. S

    Exponential Integral (Possibly integration by parts)

    Homework Statement Integrate the following equation for average energy from -infinity to infinity \int(c*x^4)*(e^(-c*x^4)/KT)dx Homework Equations c, K, T are constants \int(e^(-c*x^4/KT)) = (KT/c)^(1/4)*(2\Gamma(5/4)) The Attempt at a Solution I tried using integration by parts...
  22. Ed Aboud

    Integration by Parts: Showing $\int x^3 e^x^2 dx = e^x^2 ( \frac{ x^2 -1}{ 2 })$

    Homework Statement Show using integration by parts that: \int x^3 e^x^2 dx = e^x^2 ( \frac{ x^2 -1}{ 2 }) Homework Equations The Attempt at a Solution Integration by parts obviously. \int u dv = uv - \int v du Let u = x^3 and dv = e^x^2 dx \int x^3 e^x^2...
  23. P

    Dividing curve area in to equal parts?

    For any given curve,we can find out the area bounded by the curve. Using 'Simpson's 1/3 rule' I found out the area of the curve. Now how to divide the area into 'n' equal parts, so that total Area=sum of n areas. Thanks.:approve:
  24. S

    Integration by parts of 4th order DE

    having difficulty integrating the following equation by parts to determine if its symmetric: d4 u / dx4 + K d2 u / dx2 + 6 = 0 0< x < 1 Can someone help with this?
  25. Cyrus

    Integrate by parts because of two functions

    I found this interesting little problem when thinking about convolution: \int x( \tau) \delta(t-\tau) d\tau Normally to solve something like this you would have to integrate by parts because of two functions in \tau Using the fact that: \int u *dv = u*v - \int v*du Where...
  26. B

    Image about connection of different parts of Mathematics

    Hi guys! Today I remembered that I used to have a fantastic image (like a flow chart) about different parts of mathematics and how they are connected. In the final stage (at the top), they were connected to QFT and GR. It's down->top, at the lower end were basic mathematics (sets, boolian...
  27. V

    EndStyles of Tube fitting Parts

    Dear All, I have received 2D drawings of Tube Fitting Parts. I need to create the model and assign the properties. I like to know how to assign the end styles for different Tubing Parts and how to define the connector (tubing) points. Any help is highly appreciated. Thanks in...
  28. N

    Integration by Parts: Solving 1/(u²(a+bu)²) with Substitution

    Homework Statement 1/(u²(a+bu)²) a and b are constants u is the variable Homework Equations The Attempt at a Solution i know I am suppose to use substition by parts but i don't know what to use. thanks for help in advance
  29. K

    Integration (by parts)

    Homework Statement \int_0^1 (6t^2 (1+9t^2)^{1/2} dt) Homework Equations \int u dv = u v - \int v du The Attempt at a Solution \int_0^1 (6t^2 (1+9t^2)^{1/2} dt) =6 * \int (t^2 (1+9t^2)^{1/2} dt) = 6 * \int (t * t (1+9t^2)^{1/2} dt) Let u = t ; let dv = t (1+9t^2)^{1/2}...
  30. S

    Inclined Plane Problem Two Parts

    Homework Statement The block shown in Fig. 4-48 lies on a smooth plane tilted at an angle θ = 24.5° to the horizontal. Ignore friction. http://www.webassign.net/giancoli5/4_48.gif (visit this site for picture) (a) Determine the acceleration of the block as it slides down the plane...
  31. X

    Is My Integration by Parts on \(\int \frac{1}{(x-1)(x+2)} \, dx\) Correct?

    Homework Statement INTEGRAL 1/ (X-1)(X+2) DX Homework Equations I LET U = X+2 DU=X The Attempt at a Solution I GOT LN/(X+2)/+C I JUST DONT KNOW IF IM DOING IT RIGHT
  32. J

    Integrating Natural Log Function using Integration by Parts Method

    Integrating Natural Log Function using "Integration by Parts" Method Homework Statement The problem says to integrate ln(2x+1)dx Homework Equations I used u=ln(2x+1); du = 2dx/(2x+1); dv=dx; v=x The Attempt at a Solution So, I integrated it using that (above) 'dictionary' and I...
  33. S

    What is the Integral of f(x)g'(x) for Given Values of g(x)?

    Homework Statement Estimate \int_{0}^{10} f(x) g'(x) dx for f(x) = x^{2} and g has the values in the following table. \begin{array}{l | c|c|c|c|c|c |} \hline \hline g&0&2&4&6&8&10\\ \hline g(x)&2.3&3.1&4.1&5.5&5.9&6.1\\ \hline \end{array}...
  34. M

    I have tryed this problem 40 times and cant solve the last 2 parts

    At one instant a bicyclist is 27.0 m due east of a park's flagpole, going due south with a speed of 14.0 m/s. Then 31.0 s later, the cyclist is 27.0 m due north of the flagpole, going due east with a speed of 14.0 m/s. For the cyclist in this 31.0 s interval, what are the (a) magnitude and (b)...
  35. P

    Simple integration by parts question

    Hello, The problem I'm working on is X225x. I know you have u = x2 and du = 2x however if dv= 25x then what is v? I know if dv were say e2x than v would be 1/2e2x but for this problem would v simply be 1/5*25x? Thank you
  36. D

    Integrate ln(x)/x^4 using Integration by Parts | Homework Help

    Homework Statement Integrate \int{\frac{lnx}{x^4}dx} Homework Equations The Attempt at a Solution I get this: u = ln x, du = \frac{1}{x} dv=x^4, v=\frac{x^5}{5}dx \frac{(lnx)x^5}{5}-\int{\frac{x^5}{5}*\frac{1}{x}dx} = \frac{(lnx)x^5}{5}-\frac{6x^6}{5}dx} Am I doing this right?
  37. R

    Integration By Parts - Another Problem

    Homework Statement \int {\frac{{\cos ydy}} {{\sin ^2 y + \sin y - 6}} } The Attempt at a Solution \int {\frac{{\cos ydy}} {{\sin ^2 y + \sin y - 6}} = } \int {\frac{{\cos ydy}} {{(\sin y - 2)(\sin y + 3)}}} Now I attempt to split this into partial fractions: \begin{gathered}...
  38. Somefantastik

    Integration by parts and coefficients

    b_{n} = \frac{1}{\pi}\int^{\pi}_{-\pi}sin\theta sin n\theta d \theta let u = sin \theta, \ du = cos \theta d \theta dv = sin n \theta d \theta, \ v = -\frac{1}{n}cosn \theta = \left[-\frac{1}{n} sin \theta cos n \theta \right|^{\pi}_{-\pi} + \frac{1}{n} \int^{\pi}_{-\pi} cos...
  39. I

    Non-covariant parts of the propagator?

    I'm reading Weinberg's volume I. I don't quite understand what's the origin of the non-covariant parts of the propagator. The propagator can be calculated to be \Delta_{\ell m}(2\pi)^{-4}\int d^4q\frac{P_{\ell m}(q)\,e^{iq\cdot(x-y)}}{q^2+m^2-i\epsilon}\quad\cdots(*) where P_{\ell...
  40. D

    Integration by parts help natural log hurry tired

    Integrate the function. (3x)/(3x-2) I am spose to use integration by parts but i don't know how to integrate 1/(3x-2). anybody help??
  41. J

    What are the most interesting parts of Ted Kaczynski manifesto?

    I was going to read the whole thing but it was a long article http://en.wikisource.org/wiki/Industrial_Society_and_Its_Future#The_.27bad.27_parts_of_technology_cannot_be_separated_from_the_.27good.27_parts Do you think much of what he said was true?
  42. S

    Guys asking about this website to buy project parts

    HI I am to buy project parts. while searching online, i found this website and has a good variety of projects. In fact, I need your advice about such a website http://www.electronics-diy.com specifically about the BA1404 and TDA7000 ICs. please guide me and light the topic.
  43. J

    Decomposition of direct product into symmetric/antisymmetric parts

    Can anyone explain to me why the 3-rep of SU(3) gives 3\otimes 3 = \overline{3}\oplus 6 whereas for the 5 of SU(5) 5\otimes 5 = 10\oplus 15? I thought the general pattern was N \otimes N = \overline{\frac{1}{2}N(N-1)}\oplus \frac{1}{2}N(N+1) but this second example seems to...
  44. X

    Integration by parts trial and error

    Homework Statement \intln(7x+9)dx Homework Equations derivative of ln is 1/x The Attempt at a Solution Well I am just learning IBP so i set u=7x+9 dv=lndx but I am stuck there. How do you know which to make ur u is there a way or is it trial and error Can i split the integral as: ∫ln(7x)+∫9
  45. A

    Integration by parts problem

    Homework Statement ∫e^x+e^x Homework Equations ∫u dv= uv- ∫v du The Attempt at a Solution u= x+e^x du= e^x so it would be e^u integral = e^u = e^(e^x) +c is that correct, i know the answer is but what i just did
  46. A

    Integration by parts I believe

    Homework Statement ∫x sin^2 x dx Homework Equations integration by parts ∫u dv= uv-∫ v du The Attempt at a Solution u=x dv=1-cos2x v= 1/2 sin 2x du=dx is that correct i substituted sin^2 x= 1-cos2x Am I allowed to do that.
  47. Somefantastik

    Integration by parts; the error of my ways

    Hi all, I'm working on an ODE and ran into this integration by parts. My calculus is terrible. Can someone help? e^{2t}x = \int e^{2t}cos(t) \ dt = \frac{1}{2}cos(t) \ e^{2t} + \frac{1}{2}\int e^{2t}sin(t)\ dt = \frac{1}{2}cos(t)\ e^{2t} + \frac{1}{2}\left(-e^{2t}cos(t) + 2\int cos(t)\...
  48. A

    Integration by parts, I on this problem.

    Homework Statement ∫ (theta)^3 *cos(theta)^2 Homework Equations integration by parts ∫u dv= uv- ∫v du The Attempt at a Solution u=theta^3 dv=cos(theta)^2 du=3theta^2 v=sin(theta)^2 here's the problem do i use cos(theta)^2 equal...
  49. A

    Evaluate the integral, integration by parts

    Homework Statement ∫ln (2x+1) dx Homework Equations ∫u dv=uv- ∫ v du integration by parts The Attempt at a Solution u= ln (2x+1) dv=dx du=? v=x ok did i choose the right u and how do i derive it, do i have to use the chain rule π²³ ∞ 0° ~ µ ∑ Ω √ ∫ ≤ ≥ ± # … θ φ...
  50. A

    Solving Integrals: A Step-by-Step Guide for Integrating by Parts

    Homework Statement \text {Evaluate } \int^m_1 x^{3}ln{x}\,dx Homework Equations The Attempt at a Solution Integrating by parts, but not sure which term to substitute out...it's not turning out clean...argh I've done every other problem except for this one, can someone just...
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