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. C

    Recycling parts from other electronics

    Hi everyone, first time poster on Physics forum here. I'm working on a school project to make a device to read QR code. I'm strapped for cash so I'm trying to figure out if I can recycle some parts from used electronics. Looking for the following parts: - a graphic LCD display - an arduino...
  2. W

    Integration by parts & inv. trig fxn

    Homework Statement \int xarcsin2xdx 2. The attempt at a solution Can someone explain to me what is happening at step 2? I understand how the integration by parts was done, but where does the (1/8) or (2x) come from?
  3. W

    Applying Integration by Parts & Trig Substitution

    Homework Statement \int\sqrt{4+9x^{2}}dx Homework Equations Pythagorean Identities? The Attempt at a Solution I find it sort of cumbersome to use the special formatting here, so I hope it is okay that I just photocopied my work on paper. You can see how far I made it, but...
  4. F

    What Does an Uncertainty of 8 Parts in 1010 Mean in Experimental Results?

    Trying to answer a question that state an experiment results shows uncertainty of 8 parts in 1010. Can anyone shed some light on the meaning. I don't understand. Thank you
  5. S

    Integration by Parts: Solving Integrals without Laplace Transforms

    1. How to solve integral of (1/(t2-t))dt 2. to be solved without using laplace transforms 3. integral of( uv)= u*(integral of v) -integral of ((u')*(integral of v)) ... right? integral of (1/t^2-t) = integral of (1/t)*(1/t-1)dt = (1/t-1)*(log t) - integral((-1/(t-1)2*logt ...i don't...
  6. K

    Integration by parts and infinity

    Homework Statement integrate (x*2e^x)/(2e^x-1)2 from x=0 to infinity Homework Equations The Attempt at a Solution let t=2e^x-1 => x=ln((t+1)/2) dt = 2e^x dx Thus equation is now integrate (ln((t+1)/2))/t^2 dt from t=1 to infinity Then let u = (t+1)/2 => 2du=dt Equation now...
  7. D

    Integration by parts, don't quite know how to arrive at the given answer

    I am assuming that the solution was arrived at through integration by parts, however I am not able to completely work through it. First given: cB= XB/Vm the next step shows the solution to dcB given as: dcB=(1-dlnVm/dlnxB)(dxB/Vm)
  8. M

    Laplace by parts -> series

    Homework Statement Find analytic solution of some kind: 0&=Y''(y)-\frac{\alpha^2 [u(y) + U]}{\epsilon}Y(y) U eigenvalue, u(y) known, epsilon & alpha paramertres,and& Y thing to be found Homework Equations u(y) is a parallel flow of some kind and laplace transform given by...
  9. N

    Solving sin z=2: Equating Real and Imaginary Parts

    Homework Statement Solve sin z=2 by (a) equating the real and imaginary parts (b) using the formula for arcsin z. Homework Equations (a) sin z = sin x * cosh y + i * cos x * sinh y arccosh z = log[z + sqrt(z^2 - 1)] (b) arcsin z = -i * log [i * z + sqrt(1 - z^2)] The...
  10. B

    Real parts of two analytic functions are equal?

    Homework Statement Suppose f and g are analytic on a bounded domain D and continuous on the domain's boundary B. Also, Re\left(f\right) = Re\left(g\right) on B. Show that f = g + ia, where a is a real number. Homework Equations The maximum modulus principle states that Re\left(f\right) and...
  11. P

    Why does the LPG cylinder has to be two parts welded together

    Am a second year be student.While in a discussion in class my professor posed this question to us"Why does the LPG cylinder has to be two parts welded together".I tried searching it in net but coudn't kinda get the answer so can somebody explain it to me... And since am newbie to the...
  12. vmr101

    I(n) = ∫sin^n (x) dx (integration by parts)

    Homework Statement i)Use integration by parts to express: I(n) = ∫ sin^n (x) dx in terms of I(n-2). ii) Hence show that ∫(π/2 for top, π/4 for bottom) 1/[sin^4 (x)] dx = 4/3 Homework Equations Reduction Formula and Trig Identity [sin²(x) + cos²(x) = 1] π = pi The Attempt at a...
  13. B

    General solution of integration by parts of int(x^n*e^x)

    Homework Statement i have to create a general formula for integral of (x^n * e^x) dx using whatever method i deem appropriate. (the only way i could think of is by parts) Homework Equations int(x^n * e^x)dx int(uv')dx=uv-int(vu')dx The Attempt at a Solution i used integration by...
  14. P

    Integration by Parts: Solving ∫x*e^-x dx

    Homework Statement ∫ x * e^-x dx Homework Equations Integration by parts: Just wondering if below is correct. Not brilliant with Integration by parts and not sure if my +ve and -ve signs are correct. Some help to say if i am correct or where i have gone wrong would be brilliant...
  15. R

    Integrating the Sine Integral: Solving the Challenging Integral of sinx/x

    [b]1. The problem statement, all variables and given/known Homework Statement \int \frac{sinx}{x}dx Homework Equations The Attempt at a Solution Which method should work here? I tried integration by parts and it looks too much. Is there a way to solve it without approximating it with the...
  16. E

    Integration by Parts: Solving Homework Statement

    Homework Statement I had this integral on my physics homework and for the life of me couldn't solve it. I ended up using Maple..well wolframalpha.com because Maple's output sucks. Anyway here is the problem. \int_{0}^{\infty} x e^{-2 \alpha x}dx Homework Equations \int u dv = uv - \int v...
  17. Z

    Conjugate transpose/real and imaginary parts

    In my linear algebra text it says it's possible to define (for nxn matrix A) A_1^* =\frac{A+A^*}{2} A_2^* =\frac{A-A^*}{2i} so A=A1+iA2 It then asked if this was a reasonable way to define the real and imaginary parts of A. Is there a specific convention to define the real and imaginary parts...
  18. D

    Integration by parts and improper integral

    I would like to solve the following integral but I am unsure of the best way to solve it: \int_{0}^{H}xsin(\frac{w}{x})cos(\frac{x}{w})cosh(\frac{H}{w})dx Is it possible to use integration by parts?? Thanks in advance
  19. D

    Integration by parts and Laplace Transforms

    Hi All, This is not a homework question, I am just trying to be come quicker at integrating by parts, when performing Laplace Transforms. My textbook gives a basic example for performing the Laplace Transform of the variable t, to the transformed variable of s for the equation...
  20. A

    Integration by parts expression help

    the expression to integrate is: \int x^{3}e^{x^{2}}dx and in the spirit of "LIATE" I set my u and dv as the following: dv=e^{x^{2}}dx u=x^{3} however, doing this that I integrate dv=e^{x^{2}}dx in order to get v...and unless I'm missing something, this does not seem like an easy...
  21. F

    Strain on different parts of a cantilever

    Hey physics forums people, this is my first post ever and I am not sure if this is the right sub forum, but w.e, let's try this out anyways Homework Statement K so the problem is I've got a weight hanging on the shear centre of a cantilever and there are strain gauges all over it It is an L...
  22. A

    Another integration by parts

    problem is to integrate the following by parts: \int x\sec^{2}xdx my feeling is convert the secant term to cosine by: sec^{2}x=cos^{-2}x\Rightarrow\int\sec^{2}xdx=\int\cos^{-2}xdx then: u=\cos^{-2}x\implies du=2\sin x(\cos^{-3}x) and also: dv=xdx\implies v=\frac{x^{2}}{2}...
  23. A

    How Can I Solve This Integration by Parts Problem?

    problem is solve the following integral by parts: \int\ln(2x+3)dx I used substitution: u=ln(2x+3) \Rightarrow du=\frac{2}{2x+3}dx and for dv: dv=dx \Rightarrow v=x however, once I plug all these into my integration by parts formula, I get: x\ln(2x+3)-\int\frac{2x}{2x+3}dx and this new...
  24. S

    Integral Calc: Integrated by Parts - Is it Correct?

    Hi -- I want to integrate this integral and ask if my work is correct or not. \int^\infty_0 dx x^{\alpha-1} e^{-x} (a+bx)^{-\alpha} ---------- I want to integrate it by parts, so I have (a+bx)^{-\alpha} = v -b\alpha(a+bx)^{-\alpha-1}dx = dv x^{\alpha-1} e^{-x} dx = du...
  25. M

    Courses Would I have to teach my self some parts that aren't covered in the course?

    I am taking calculus b but for some reason it seems to be a shorter version according to my instructor. We are using james stewart 6th edition but only taking chapters from 7-11 excluding 10 which are 7_Inverse Functions: Exponential, Logarithmic, and Inverse Trigonometric Functions...
  26. V

    Where have I gone wrong in this integral by parts

    Homework Statement ∫ ln(2x+1)dx Homework Equations The Attempt at a Solution ∫ ln(2x+1)dx 1/2∫2ln(2x+1)dx t = 2x+1 dt = 2dx 1/2∫ln(t)dt u = ln(t) du = 1/t dt dv = dt v = t tln(t) - ∫ t*1/t dt tln(t) - ∫ dt tln(t) - t 1/2*[(2x+1)ln(2x+1) -...
  27. Saladsamurai

    Integration by Parts: With Partials

    Homework Statement I don't know why, but the partials are really confusing me here. I need to integrate the following expression in a derivation: I = \int_0^\delta v(x,y)\frac{\partial{u(x,y)}}{\partial{y}}\,dy \qquad(1)Homework Equations I am supposed to integrate by parts here. \int...
  28. J

    How can integration by parts be used to solve this integral?

    Homework Statement integral of x^2ln(x)dx Homework Equations The Attempt at a Solution u=ln(x) du= 1/x dv=x2dx x^3/3 integral x^2ln(x)dx = ln(x)x^3/3-intergral(x^3/3)(1/x)
  29. H

    Definite integration by parts with sub

    hello, i am stuck on how to do this I know how to do it for an indefinite integral, but it gets confusing for a definite integral. from my knowledge, when doing a definite integral, you have to change the upper and lower limit. but when it comes to integration by parts for a definite integral...
  30. D

    Integration by Parts: Solving \int{x^2tan^{-1}xdx}

    Homework Statement \intx^2tan^{-1}xdx The Attempt at a Solution \int{x^2tan^{-1}xdx} \int{x^2tan^{-1}xdx} = \frac{x^3}{3}tan^{-1}x-{\frac{1}{3}}\int \frac {x^3}{1+x^2}dx let {}u=1+x^2, \frac{du}{2}=xdx \frac{x^3}{3}tan^{-1}x- \frac{1}{6}\int (1-1/u)...
  31. M

    Integration by Parts: Solving \int t sin(2t) dt

    Homework Statement \int t sin(2t) dt Homework Equations Integration by parts formula: \intudv = uv - \intvdu The Attempt at a Solution I chose t to be u so, u=t du=dt dv=sin(2t)dt v=(sin)^2 (hope that's right. I used double angle formula to change sin(2t) into 2sint...
  32. F

    How to solve for the integral of sin(3x) times x using integration by parts?

    Homework Statement I have work these two problems, but in the first one #4 I feel like I'm missing something a step or something. and in the second problem I'm just lost, I can't finish it so will you please assist me. your help is appreciated. Homework Equations thanks a lot. The...
  33. Q

    Master 3D Modeling with Movable Parts: Create Dynamic Designs with Ease

    I'm looking for a 3d modeling software that let's me interact with rivets and joints to see how it would move. Basically I want to design a contraption made out of wooden slats and hinges/joints that open and folds into certain shapes. I would prefer software with a very low learning curve. Also...
  34. H

    A Sequence defined by 2 parts

    Homework Statement The sequence an = 0, if n contains the digit 9 an = 1/n. if n does not contain the digit 9 does the series\sum an converge? Homework Equations The Attempt at a Solution I have this idea to separate this series into two subseries - the harmonic and the...
  35. B

    Integration by parts of a dot product scalar integrand

    Homework Statement Is this true or false? \int_V {\vec \nabla \Phi \bullet {\bf{E'}} \cdot {d^3}x} = \vec \nabla \Phi \bullet {\bf{E'}} - \int_V {\Phi \cdot \vec \nabla \bullet {\bf{E'}} \cdot {d^3}x}
  36. V

    How can I solve the integral 2 ∫ t cos(t) dt using integration by parts?

    Homework Statement I have to solve this integral S cos(x^1/2)dx where S is the integral symbol Homework Equations The Attempt at a Solution the book tells me to use substitution and then integrate by parts so i say u = x^1/2 du = 1/2*x^-1/2 then i can write 2 S...
  37. P

    Solve Integral [xln(x^2+9)] Using Tabular Method

    Homework Statement Solve the integral of [xln(x^2+9)] wrt x using the tabular method. Homework Equations By parts using the tabular method. The Attempt at a Solution u: 1. ln(x^2+9) 2. 2x/(x^2+9) dv: 1. x 2. (1/2)x^2 3. (1/6)x^3 The answer for now is ...
  38. K

    A few integration by parts problems

    Homework Statement Hello. I am doing some problems on integration by parts and got stuck on the following problems. Any help would be appreciated. i. \int \arcsin x dx ii. \int_{0}^{1} x \ln (9+x^2) dx iii. \int x^2 \arctan x\, dx Homework Equations u\,du=uv-v\,du The Attempt at a...
  39. M

    Integration by parts for a definite integral

    [PLAIN]http://img25.imageshack.us/img25/8933/lastscante.jpg I am new to integration by parts and am not sure what boundries to use when eveluating v on the bottom right.
  40. R

    Integration by Parts definite integral

    Homework Statement The definite integral of from 0 to 1 of ∫ (r3)dr/sqrt(4+r2)Homework Equations ∫udv = uv - ∫vdu ∫du/sqrt(a2 - u2) = arcsin(u/a) + C ∫du/(asqrt(a2 - u2)) = (1/a)arcsec(u/a) + C The Attempt at a Solution I made u = (4+r2)-1/2 because I thought it easier to get it's...
  41. O

    Integration by parts and substitution

    Homework Statement Integrate: \sqrt{x}e^\sqrt{x}Homework Equations See aboveThe Attempt at a Solution Well I started off first by taking t=sqrt(x) but that didn't get me very far. So then I decided to make x equal to t^2 which sort of worked. After hours of struggle I decided to have a look at...
  42. Z

    Integration by Parts: Formula & Real/Non-Integer n

    is the following formula of integration by parts \int_{-\infty}^{\infty}dxf(x)D^{n}g(x) = (-1)^{n} \int_{-\infty}^{\infty}dxg(x)D^{n}f (x) valid for real or non-integer n? the problem i see here is the term (-1)^{n} , which may be not so well defined for non-integer 'n'
  43. T

    How to Solve an Integration By Parts Problem?

    Homework Statement Homework Equations The Attempt at a Solution I tried this problem and couldn't figure it out so I went and got the solution. However, I don't understand step 6 of the solution. I'm not sure how (n-1)\int\sin^{n-2}x(1-\sin^2x)dx=(n-1)\int\sin^{n-2}dx-(n-1)\int\sin^nx dx
  44. B

    Separable differential equation and Integration by parts

    Homework Statement dy/dx = e^ysin^2x/ysecx Stewart 6e 10.3 # 8 Homework Equations The Attempt at a Solution ydy/e^y = sin^2xdx/secx e^-ydy = sec^-1xsin^2xdx Integration by parts u = e^-y du = -e^-y dv = ydy v = y^2/2 ∫udv = e^-yy^2/2 + ∫y^2/2e^-y = y^2/2e^y +...
  45. K

    How to eliminate imaginary parts of complex expression?

    Hi, I have a problem on how to convert the imaginary parts of expression into all real parts. For example: x1 = - (a + ib) x2 = (a + ib) x3 = - (a - ib) x4 = (a - ib) My question is that how to express x1, x2, x3 and x4 in terms of real parts only without imaginary parts. I have used...
  46. C

    Integration by Parts to find integral

    Homework Statement find the integral of cot^(-1)of (5x) Homework Equations Integration by parts The Attempt at a Solution u = x du = dx dv = cot ^ (-1) v = ? and then i would plug into equation [uv- integral of vdu ]
  47. M

    Double Integral Plus Integration by Parts with Natural Log Problem

    Homework Statement My homework problem is the double integral of y/1+xy dxdy. It is a definite double integral and both integrands have the values of a = 0 and b = 1. Homework Equations Integration by parts: uv - int(vdu) The Attempt at a Solution My first step of the double integral is I...
  48. K

    Integration by parts possible?

    Homework Statement Calculate: \integral \frac{1}{(x^2+1)(x+1)} Homework Equations \integral f(x) g'(x) = f(x) g(x) - \integral f'(x) g(x) + C The Attempt at a Solution I've tried using both 1/(x+1) and 1/(x^2 + 1) as dv, but both end up in another integral I can't solve, one...
  49. A

    Shell gets separated in two. What's v of two parts?

    Homework Statement The shell of a shotgun, after being fired, with a velocity of v=1000 m/s gets split into two parts with equal masses. One of the two parts continues to move on the same direction as the whole (not separated) shell did, with a velocity of v=1500 m/s. a) Find the velocity...
  50. R

    Integration by parts and characteristic functions

    Homework Statement Given characteristic functions f and g on the intervals [1,4] and [2,5] respectively. The derivatives of f and g exist almost everywhere. The integration by parts formula says \intf(x)g'(x)dx=f(3)g(3)-f(0)g(0)-\intf'(x)g(x)dx. Both integrals are 0 but f(3)g(3)-f(0)g(0) is...
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