Integrating Definition and 940 Threads

  1. Wellesley

    Integrating Factor for Exact Differential Equation

    I can see why y2 is an integrating factor, but I don't know how this answer can be derived. Do you use: \frac{N_{x}(x,y) - M_{y}(x,y)}{M(x,y)} Where M (x,y) = 4(x3/y2)+(3/y)]dx, and N = 3(x/y2)+4y dy When I try and solve this, I get a very complex integrating factor...
  2. P

    Integrating Over All Orientations: Solving Eqn (1)

    So I need to inegrate over a solid angle, in which every possible orientation is considered (we are doing scattering events in which we assume every possible angle is possible), thus I need to solve \int d\Omega_1 d\Omega_2 d\Omega_3 Eqn (1). Now I know \int^{2 \pi}_{0}...
  3. Z

    Integrating Torque With Force as a Function of Radius

    Homework Statement In this problem, I am asked to find the total torque acting on a device consisting of two open half-cylinders connected to a shaft rotating in a fluid. To clarify, they are half-cylinders in the sense that they have been cut in half in the lengthwise direction and are...
  4. R

    Integrating in polar coordinates (volume)

    Homework Statement The solid bounded by the parabolids z = 3x^2 + 3y^2 -7 and z = -x^2 -y^2 + 9 Homework Equations The Attempt at a Solution Ok so i set the two z equations into polar form and came up with 3r^2 = 7 and r^2 = 9 I thought that r went from (7/3) ^(1/2) to 3 and...
  5. R

    Integrating Factor: -g(m/g) and its Derivative

    In the following problem how does -g end up becoming -g(m/g)? Isn't the derivative of -g just (-g^2/2)? http://users.on.net/~rohanlal/integfact.jpg
  6. A

    Integrating a Constant Divided by a Linear Function of x

    Okay well, I looked through my calculus notes and textbook and I can't find what to do when you are integrating a function of the type a/u where a is a constant and u is some linear function of x. I know that the integral of 1/x is ln(x) but what about when you have something like \int...
  7. O

    Question integrating |f(z)||dz| over a contour C

    Homework Statement I want to compute \int_{C}^{}{|f(z)||dz|} along the contour C given by the curve y=x^2 using endpoints (0,0) and (1,1). I am to use f(z)=e^{i\cdot \texrm{arg}(z)} Homework Equations The Attempt at a Solution I know that for all complex numbers z, |e^{i\cdot...
  8. A

    Integrating 1/(2x^2 + 3x + 1)[(3x^2 - 2x + 1)^(1/2)]

    Homework Statement integrate Homework Equations 1/(2x^2 + 3x + 1)[(3x^2 - 2x + 1)^(1/2)] The Attempt at a Solution
  9. N

    Integrating Complexity: Indefinite Integral of e^(4x+(e^4x))

    Homework Statement Indefinite integral: e^(4x+(e^4x)) Homework Equations I'm thinking integration by parts, involving UV minus integral of Vdu The Attempt at a Solution So I saw that this can be split into two: e^(4x) times e^(e^4x)). The latter is a bit complicated. I...
  10. A

    I'm really having a problem integrating this equation, infact i have no idea

    Homework Statement Please tell me how to integrate this... Homework Equations [(2x + 4)][(2x^2 + 3x + 1)^(1/2)] The Attempt at a Solution
  11. H

    Integrating Trigonometric Functions with Irrational Exponents

    Homework Statement The integral from 0 to pi/2 of 1/(1 + (tanx)^sqrt2) dx. Homework Equations trig identities? The Attempt at a Solution I tried some substitutions but it just made the problem more complicated. I also multiplied by (tanx)^sqrt2 in the numerator and denominator in...
  12. C

    How Can You Integrate xsinxcosxdx Using Exponential Form?

    How do you integrate xsinxcosxdx
  13. tony873004

    ODE, Integrating Factor method

    I'm trying to follow this example from class notes. x^2 \frac{{dy}}{{dx}} + xy = 1,\,\,y\left( 1 \right) = 2 Divide through by x^2 to set it up in a form for using the integrating factor method. \frac{{dy}}{{dx}} + \frac{y}{x} = - \frac{1}{{x^2 }} I'm not sure where the minus...
  14. D

    Integrating Exponential Functions to Solving e^(-(x^2)/2)

    Hi! I want to know how to intergrat e^(-(x^2)/2) . Someone told me to use the intergration of e^x= 1+ x + (x^2) /2!+ ...(X^n)/n! ... is that sounds right?? and if it is i got pi as an answer for e^(-(x^2)/2) , is that the right answer?
  15. A

    Sequence of functions; uniform convergence and integrating

    Homework Statement The sequence fn: [-1,1] -> R, fn(x)= nxe-nx2 converges pointwise to f(x)= 0, x in [-1,1]. Can you verify the following: limn->\infty (\int^{1}_{0}fn(x)dx) = \int^{1}_{0} (limn->\infty fn(x))dx Homework Equations Theorem: If fn is continuous on the interval D for every...
  16. K

    How Do I Integrate a WKBJ Semi-Classic Integral with a Square Root?

    Homework Statement I am having a problem integrating in a WKBJ semi-classic integral. Well it's this : I have to integrate \int_{0}^{\sqrt{m}E}\sqrt{E-\frac{x}{\sqrt{m}}}dx Homework Equations Actually I don't have that much experience at integrating, so could you somehow show me how to...
  17. S

    Integrating Equations with Exponents: A Challenge

    Homework Statement Homework Equations The Attempt at a Solution Homework Statement Homework Equations u = 1+tant du = sec^2(t) dt dt = du / sec^2(t) The Attempt at a Solution It seems like I should be using substitution in the equation, however the exponent is...
  18. M

    Integrating Int((5+10y^4)dy/(y+2y^5)) - A Step-by-Step Guide

    Homework Statement I want to deal with this int((5+10y^4)dy/(y+2y^5)) Homework Equations integration, substitution, partial fractions? The Attempt at a Solution I tried a bunch of random things. I think it hs to do with substitution because if I make u=y+2y^5, du/dy=1+10y^4...
  19. F

    How can I integrate v² / (v² + 4) using arctan and u substitution?

    Homework Statement how do i integrate v^2 / v^2 + 4 Homework Equations i understand this has something to do with arctan but if i use u substitution to let v=(u/2) so (on the bottom) it becomes (1/4)(1+(v/2)^2) there's still a v^2 on the top which the u substitution does not...
  20. J

    Integrating Using Arctan: Solving for the Integral of 1/(x^2+11x+29)

    Homework Statement Integrate 1/(x2 +11x +29) Homework Equations The Attempt at a Solution I'm doing something wrong, but can't figure out what... Complete the square so that the denominator equals (x+2)2+25 Then divide by 25: ((x+2)2)/25 + 1 Move that 25 into the squared...
  21. E

    Integrating ln(t+1) from 0 to e^2x?

    Homework Statement How would I begin to integrate ln(t+1) from 0 to e^2x? Homework Equations d/dx[log base a of u]=1/(lna)u du/dx Can the original equation be manipulated to use this derivative? The Attempt at a Solution Not sure where to start.
  22. M

    Integrating from 0 to 200 of 1/(14-(.0003x^2))

    I can't figure out how to this integral. I keep coming up with the wrong answer. Can someone please show me a detailed solution?
  23. C

    Integrating dP/dr over the Sun

    Homework Statement Consider the Sun to be a sphere of hydrogen gas of uniform density equal to its average density (1440 kg/m3). a) Integrate the equation of hydrostatic equilibrium for dP/dr from the Sun’s radius to the core to estimate the central pressure in Pa and in atmospheres...
  24. A

    Integrating Functions with Double Poles: A Contour Integral Approach

    Hi, Can someone tell me how to integrate functions which have a branch point and a pole (of order > 1) on the x-axis. Specifically, I ran into the following problem while playing around with contour integrals, which has a double pole at x = -2 . I tried to do this with a keyhole contour...
  25. A

    Integrating odd functions with infinite discontinuity:

    If an odd function has an infinite discontinuity in its domain, can it be integrated (such that a convergent finite emerges) with that domain included? For example: \int_{-1}^2 \frac{1}{x^{-3}} dx. Intuitively, it can be simplified to \int_1^2 \frac{1}{x^{-3}} dx and thus the infinite...
  26. S

    Integrating Factor and Unintegratable Term

    I was given the following ODE to solve and it seemed simple enough. However, after you have used the integrating factor the integral is not integratable. y' = (1+x^2)y +x^3, y(0)=0 Find y(1) if y(x) is the solution to the above ODE. So I put it in the proper form of: y' + (-1-x^2)y...
  27. H

    Integrating the Cartesian form of Coulomb's law

    Hi, I want to calculate the potential energy between two opposite charges (a dipole) and I know how to integrate Coulomb’s law in the polar form, i.e. in terms of “r” \[...
  28. F

    Integrating with polar co-ordinates

    revising for an exam and have the question let I=∫lim ∞ to 0 e-x2 dx. since x is a dummy variable here, replace it with y to get a second expansion for I. Multiply these two together to get a double integral for I2. Transform into polar co-ordinates noting that dxdy corresponds to r dr d♂. Carry...
  29. T

    LaTeX Integrating Momentum Space: Replacing hslash with d

    does anyone knw the code for how to produce the d slash notation in the integration measure for momentum space? Where (d slash)^n X=(d^n)X/((2pi)^n). Basically all i want to do is replace the h: \hslash with a d.
  30. K

    Integrating e^-4tsint by Parts

    Homework Statement Integrating -e-4tsint Homework Equations Our tutor suggested we did this by integrating by parts in a cyclic fashion and things would cancel out The Attempt at a Solution Taking u = sint t; thus u'=cost And v'=-e-4t; thus (1/4)e-4t \int-e4tsint =...
  31. P

    Integrating a Vector Field Over a Circular Disk

    Hi, How do integrate this? I wish to see it step by step and I'm glad for any help i can get. \int_{ \vec{r}\in{A}} \frac{ \vec{v}+ \vec{\omega}\times\vec{r}}{| \vec{v}+ \vec{\omega}\times\vec{r}|}d^{2}r where A is area of disk with radius R.
  32. F

    Integrating e^(-3x) with u-Substitution

    Homework Statement before we start, i don't know how to do the integral sign, so we'll use [ I need to integrate [ e^(-3x) / 1 + e^(-3x) Homework Equations I've always had trouble with doing integration with e The Attempt at a Solution I used u=1+e^(-3x) du = -3e^(-3x)...
  33. Y

    Integrating factor for solving equation problem.

    Homework Statement Find the gerneral solution of the differential equation below: dy/dt=(-y/t)+2 Homework Equations none The Attempt at a Solution my solution by using integrating factor: 1.find the homogenous solution first dy/y = -1/t dt you get ln(y) = -ln(t) when...
  34. H

    Why Should You Integrate a Power Series from Zero?

    Hello, I have a power series, and a problem with an integration with it, I don't understand why I should integrate it from zero at one point. I have attached a detalied explanation of the problem. http://img79.imageshack.us/img79/5156/powerseriespt4.jpg Any help would be greatly appreciated.
  35. G

    Proof of Fubini's Theorem: Integrating h(x,y)

    What's the proof of this fundamental theorem? Let (X,B,u) and (Y,C,v) be sigma finite measure spaces, Let f in L1(X,B,u) and g in L1(Y,C,v). Let h(x,y)=f(x)g(y). Then, h is in L1(XxY,BxC,uxv) and \int hd(u\times v)=\int fdu \int gdv should be an easy application of fubini,but i really have no...
  36. M

    Integrating x^2 sin x: Find Exact Value of Abs(-pi/2 to pi/2)

    The question asks me to integrate x^2 sin x dx and then use it to find the exact value of the integration of abs ( x^2 sin x dx) with upper limit of pi/2 and lower limit of -pi/2. I have found the integration of x^2 sin x dx which is -x^2 cosx + 2xsinX + 2 cosx + C but after putting in the...
  37. H

    How Do We Show Integral Unity of Transformed Functions?

    Hello, I tried this in analysis but maybe it is a more topological question. If given a function f on R such that \int_R f(x)dx = 1 and is decreasing and 1-lipschitz, show that the function g(y) = min{x,f(x)} where y = x-f(x) and x>=0, also satisfies \int_Y g(y)dy=1. I really would...
  38. T

    Integrating Half-Loop Radius R: Confused?

    I can't seem to integrate this correctly. I only need the half loop integration, as i have the correct integration for the infinite lines. Homework Statement We start with the top half of a half-loop of radius R, centered at the origin, with infinite line segments traveling in the +/- x...
  39. M

    Integrating x^2/((x^2-1)^(1/2))

    Homework Equations Need to integrate x^2/((x^2-1)^(1/2)). The Attempt at a Solution I first broke the equation into (x^2-1)^(1/2) + (x^2-1)^(-1/2) Hence Integral (x^2/((x^2-1)^(1/2))) = Integral((x^2-1)^(1/2)) + Integral((x^2-1)^(-1/2))) Further on Integral((x^2-1)^(1/2)) is an...
  40. D

    Integrating through singularities

    I am a little bit confused about dealing with integrals around singularities because my professor seems to treat some situations more rigorously than others. We talked this integral and said \int_{-\infty}^{\infty}\frac{1}{x^3} dx = undefined This seems a little bit unintuitive to me...
  41. J

    Integrating sec x dx: Multiply by \frac{tan x + sec x}{tan x + sec x}

    Homework Statement By multiplying the integrand sec x dx by \frac{tan x + sec x}{tan x + sec x} find the integral of sec x dx Homework Equations d/dx sec x = tan x.sec x d/dx tan x = sec^2 x The Attempt at a Solution sec x dx(\frac{tan x + sec x}{tan x + sec x}) => \frac{tan...
  42. E

    Integrating Work from Force(time)

    Hi folks: Question for you guys. I've generalized a question that keeps coming up in class...but that keeps going unexplained. This is a somewhat involved problem which requires integrating force to find work. Thing is, force is always integrated as a function of position NOT time. This type of...
  43. T

    Two questions regarding integrating items

    Homework Statement I have a couple of questions about some intriguing looking equations. Firstly, I have to integrate: \frac{sin\theta}{cos\theta} d\theta Is there an answer to just dividing them? because sin/cos = tan, but that doesn't seem to help? Secondly, I have to integrate...
  44. B

    Integrating Gaussian functions with erf

    Homework Statement I'm doing a problem on Gaussian functions (there are other constants to make it interesting, but I've removed them here): 1. \int_{0}^{x} e^{-x^2} dx 2. \int_{0}^{x} x e^{-x^2} dx 3. \int_{0}^{x} x^2 e^{-x^2} dx We know that erf(z) =...
  45. Z

    How Do You Integrate Over an Octant for \(\frac{1}{x^2+y^2+z^2}\)?

    \int^{1.5}_{0}\int^{1.5}_{0}\int^{1.5}_{0}\frac{1}{x^2+y^2+z^2}dxdydz I tried converting this to spherical and only integrating over a quarter of the octant but with no luck. Can someone please point me in the right direction. Thanks!
  46. 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...
  47. A

    Integrating seperable equation

    Homework Statement Separable equations dy/dx = y * e^(sinx +cosy) and dy/dx = sin(x^y) The Attempt at a Solution For the first problem, I did dy/dx = y * e^(sinx) * e^(cosy) and separated. However, I can't figure out how to integrate e^(sinx)dx on the right. Did I do somehting wrong? I...
  48. D

    How Do You Solve the Integral of (e^ax)sin(bx) Using Integration by Parts?

    How do I integrate (e^ax)sin(bx)
  49. J

    Integrating inverse trig functions

    I was working on this problem \int{\frac{x^3}{x^{2}+1}}dx I at first tried to use one of the inverse trig functions but couldn't get the form to match...should I try to use log properties...making the denominaor u and trying to get the numerator 1?
  50. M

    Integrating the rational fractions

    please... i need a help in integrating the partial fractions i can't proceed to the integration part if i don't understand the patter in finding the constant... that is... if the given is: ʃ ( (x^5+1) / ((x^3)(x+1)) )dx then; ʃ ( x-2 + ( 4x^3+1 ) / ( x^4 + 2x^3) ) ʃ ( x-2 + (...
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