Form Definition and 1000 Threads

  1. L

    Online calculator that can form an equation of a curve

    Does anyone know of an online calculator that can form an equation of a curve with complex values and lots parameters? An advanced curve fitting calculator Y= C1(1/(1+C2e^C3x) for example
  2. S

    Optical tweezers for manipulating atoms together to form new structure

    I am trying to figure out a method for using optical tweezers to manipulate individual atoms into new meta-material structures. I understand this would require a very complicated process. I thought of some general steps this process might use. This is roughly what I think it might require...
  3. Q

    What exactly is differential form?

    I'm reading about multlinear algebra and I'm stuck at differential form and outer product. The definitions involve tensor product and quotient set and I really cannot grab the concrete idea of the differential form. Can someone explain in a somewhat layman term what is differential form...
  4. J

    Why is the solution in the form of Ce^kx ?

    Why is the solution to linear differential equations with constant coefficients sought in the form of Ce^kx ? I have heard that there is linear algebra involded here. Could you please elaborate on this ?
  5. B

    Tautologous Form: What Does It Mean?

    Hello everyone, I am re-reading the introductory section of Loomis and Sternberg's Advanced Calculus text. The sentence that I have come across which is giving me slight trouble is "Indeed, any valid principle of reasoning that does not involve quantifiers must be expressed by a...
  6. W

    Differential Form on Product Manifold

    Hi, I have an exercise whose solution seems too simple; please double-check my work: We have a product manifold MxN, and want to show that if w is a k-form in M and w' is a k-form in N, then ##(w \bigoplus w')(X,Y)## , for vector fields X,Y in M,N respectively, is a k-form in MxN. I am...
  7. D

    MHB Help Me Solve $\text{Im}(z^3)$ in Rectangular Form

    I don't how to proceed further Let $z=x+jy$ find in rectangular form: 1. $\text{Im}(z^3)$ this is where I can get to, $\text{Im}(x^3+3x^2jy+3xj^2y^2+j^3y^3)=\text{Im}(x^3+3x^2jy-3xy^2-jy^3)$ please help me.
  8. powerof

    Help with matrix form of the imaginary unit, i

    While investigating more about complex numbers today I ran across the 2x2 matrix representation of a complex number, and I was really fascinated. You can read what I read here. As I understand it, you write z in its binomial form but instead of "1" you use the identity matrix, I, and for i...
  9. J

    Closed integration of exact form

    If ##\omega## is an exact form ##( \omega = d\eta )## and ##\Omega## is the region of integration and ##\partial \Omega## represents the boundary of integration, so the following equation is correct: $$\\ \oint_{\partial \Omega} \omega = 0$$?
  10. I

    Can a body in space form a sphere?

    So this is some what of a silly question, I was bored and watching YouTube and there was a guy trying to say that the Earth is hollow ( crazy people are funny to watch) but it got me thinking could a planet form so that it was hollow? Or could a something like a small moon be hollowed out? I...
  11. R

    Is it possible to convert 2D coordinates of point to 3D form ?

    Hello everyone ,i have captured car positons at differents frames.http://www.imagesup.net/pt-7140205392313.png%5D%5BIMG%5Dhttp://www.imagesup.net/dt-7140205392313.png Suppose car's(left side car which is coming towards us) centroid is at video frame1 is P(x1,y1) and Q(x2,y2) at video frame4...
  12. M

    Find roster form of the given Set

    Let B be the non empty sets, B ={(x,y):y = e^x, x belongs to set of real numbers} Write the set in roster form.
  13. M

    MHB Canonical form of the hyperbolic equation

    Normal form of the hyperbolic equation Hey! :o I am looking at the following in my notes: $$a(x,y) u_{xx}+2 b(x,y) u_{xy}+c(x,y) u_{yy}=d(x,y,u,u_x,u_y)$$ $$A u_{\xi \xi}+ 2B u_{\xi \eta}+C u_{\eta \eta}=D$$ $$A=a \xi_x^2+2b \xi_y \xi_x+c \xi_y^2 \ \ \ (*)$$ $$B=a \xi_x \eta_x +b \eta_x...
  14. J

    General form of the solutions of polynomials

    I was studying a article that solves the cube and quartic equation in the inverse sense: ##x = \sqrt[3]{A} + \sqrt[3]{B}## ##x = \sqrt[4]{A} + \sqrt[4]{B} + \sqrt[4]{C}## https://www.physicsforums.com/attachment.php?attachmentid=70239&stc=1&d=1401676309I found this relationship too...
  15. K

    How does a nebula form from a neutron star

    Here is my understanding, please correct me if I am wrong, thanks At the end of the giant stage of a star, it experiences a supernova explosion, and turns into a neutron star (could be pulsar) or black hole, the explosion releases a lot of its matter. Here is what I don't understand: 1...
  16. K

    Can O2 combine with H2 to form water without activation energy?

    Let say that I have hydrogen gas and oxygen gas mix together, is there any chance that some H2 and O2 will react to form water without doing anything to it? I know that there needs to be activation energy to start the reaction, but are there any chance of reaction happening without activation...
  17. powerof

    Prove that all possible lines in function of m form a plane

    Homework Statement We are given a point A(1,1,1) and a vector v=(m-1,3m-5,2m-6). We are asked to write the parametric and continuous (I don't know if that's the appropriate term; in Spanish it's called "forma continua" but you'll see right away what I mean) equations of the line formed by these...
  18. T

    Flaw in the integral form of faradays law with large loops

    The situation is as such. you have a magnetic passing through a loop(loop 1)of wire as some time t, say you also have a larger loop of say one light year in radius surrounding loop 1, call this loop 2. at some time t the magnetic field is shut off. when this happens would loop 2 instantaneously...
  19. BiGyElLoWhAt

    Help with finding a determinant's general form

    For a homework assignment I need to find the determinant of: ##\left | \begin{array}{cccc} a^0 & b^0 & c^0 & d^0 \\ a^1 & b^1 & c^1 & d^1 \\ a^2 & b^2 & c^2 & d^2 \\ a^3 & b^3 & c^3 & d^3 \\ \end{array} \right | ## I've reduced my matrix, through linear combinations and column...
  20. T

    Helicity is different form Spin for massless particle(photon)?

    As we know photon's helicity are \pm1. Helicity is the projection of the spin S onto the direction of momentum, p, which is considered as Sz. What about Sx and Sy? They are both ZERO?
  21. O

    Differential form of Gauss' theorem with dielectrics

    Hi all, I'm stuck on this incompatibility within the differential form of Gauss' thearem (or Maxwell's first equation) with dielectrics. \vec{\nabla}\cdot\vec{E}=\frac{\rho_{free}+\rho_{bound}}{\epsilon_{0}} \rho_{bound}=-\vec{\nabla}\cdot\vec{P} But with a linear, homogeneous...
  22. B

    How Much Friction Is Needed to Prevent Leakage in a Cubical Water Tank?

    Homework Statement A water tank is formed by sliding four identical cubical blocks together. All edges are watertight. Each block has mass M and is L meters on each side. You wish to fill the tank to its brim, i.e. to depth L. What is the minimum coefficient of static friction between the...
  23. T

    Is there a short form for this equation?

    I am trying to write down a compact form of S = A+L/(B+C)+L/(B-C), does it make sense in general to write down S = A+L/(B\pmC)? Update: I have simplified it too much in the minimal working example, the denominators is actually more complicated, let me elaborate...
  24. ChrisVer

    Is There a Symmetric Form of the Dirac Lagrangian?

    Is there any way to write the Dirac lagrangian to have symmetric derivatives (acting on both sides)? Of course someone can do that by trying to make the Lagrangian completely hermitian by adding the hermitian conjugate, and he'll get the same equations of motion (a 1/2 must exist in that...
  25. M

    Is Delta H of formation the same for NH4NO3 Aqueous and in Solid Form?

    I am doing a project in Chemistry and I need to use Hess' Law to cancel two equations and if in one equation the NH4NO3 is solid and in the second one the NH4NO3 is aqueous. The equations are: 1: NH4NO3 (s) + HCl (aq) --> HNO3 (aq) + NH4Cl (aq) 2: NH4OH (s) + HNO3 (aq) --> H2O (l) + NH4NO3...
  26. J

    Solutions for diff equation in form of series

    Given the following diff equation: ##(1 - D)y(x) = f(x)##, being D = d/dx, the "implicit" solution is: ##y(x) = \frac{1}{1-D}f(x)##, so, for "explicit" the solution is necessary to expand the fraction 1/(1-D) by identity: ##\frac{1}{1-x}=\sum_{0}^{\infty}x^n \Delta n##, but this infinity series...
  27. B

    Cylindrically symmetric line element canonical form

    Hello, What is the most general cylindrically symmetric line element in the canonical form? Best regards.
  28. N

    Second order differential equation form

    A second order differential equation form d2y/dx2 = f(x,y,dx/dy) How do I read the language on the right hand side?
  29. M

    Weak Form of the Effective Mass Schrodinger Equation

    Hi, I am numerically solving the 2D effective-mass Schrodinger equation \nabla \cdot (\frac{-\hbar^2}{2} c \nabla \psi) + (U - \epsilon) \psi = 0 where c is the effective mass matrix \left( \begin{array}{cc} 1/m^*_x & 1/m^*_{xy} \\ 1/m^*_{yx} & 1/m^*_y \\ \end{array} \right) I know that...
  30. S

    General expanded form of (x+y+z)^k

    Hi, (hope it doesn't seem so weird), I'm looking for a general expanded form of (x+y+z)^{k}, k\in N k=1: x+y+z k=2: x^{2}+y^{2}+z^{2}+2xy+2xz+2yz k=3: x^{3}+y^{3}+z^{3}+3xy^{2}+3xz^{2}+3yz^{2}+3x^{2}y+3x^{2}z+3y^{2}z+6xyz k=4: x^{4}+y^{4}+z^{4}+4xy^{3}+4x^{3}y+4xz^{3}+4x^{3}z+4yz^{3}...
  31. R

    Form of the displacement, y(x,t), for the normal modes of a string

    Homework Statement The displacement, y(x; t), of a tight string of length, L, satisfies the conditions y(0, t) = \frac{\delta y}{\delta x}(L,t) = 0 The wave velocity in the string is v. a) Explain what is meant by a normal mode. Give the form of the displacement, y(x; t), for the normal...
  32. M

    How can a proton form a neutron?

    This is related to a homework problem but I want to understand it as well. How can a proton break up into a positron and neutron when a neutron clearly has a greater mass than a proton?
  33. M

    MHB Eigenvalue problem of the form Sturm-Liouville

    Hey! :o I have the following exercise and I need some help.. $"\text{The eigenvalue problem } Ly=(py')'+qy=λy, a \leq x \leq b \text{ is of the form Sturm-Liouville if it satisfies the boundary conditions } p(a)W(u(a),v^*(a))=p(b)W(u(b),v^*(b)). \text{ Show that the boundary conditions of the...
  34. R

    Collision - a ball and string form a pendulum

    Collision -- a ball and string form a pendulum... 1. A 1.0-kg ball is attached to the end of a 2.5-m string to form a pendulum. This pendulum is released from rest with the string horizontal. At the lowest point in its swing when it is moving horizontally, the ball collides elastically with a...
  35. M

    MHB Normal form of the differential equation

    Hey! :o I have the following exercise: Write in the normal form the differential equation $$u_{xx}+\frac{2y}{x}u_{xy}+\frac{y^2}{x^2}[(1+y^2)u_{yy}+2yu_y]=0$$ Hint: You can suppose that the one new variable is given by $\xi=x$ I have done the following: $a=1, b=\frac{y}{x}...
  36. J

    Calculating velocity of water flow form tap

    Homework Statement A measuring cylinder collects 475 mL of this water in a minute. At the top the diameter of the stream is 0.700 cm. Homework Equations What is the velocity of the stream 20.0 cm below the top? The Attempt at a Solution im not sure which formula to use? i was...
  37. B

    Will a precipitate form? Molar solubility question

    Homework Statement Hello all, This is a problem on a worksheet I was given and I am stumped! Statement: Will a ppt form when 35.00 mL of 1.0x10^-3 M CoSO4 is mixed with 15.00 mL of 7.50x10^-4 M Al2(SO4)3 and 200 ml of a buffer which is .200 M NH3 and .200 M NH4Cl? I do not need the answer...
  38. M

    Weak Form of the Poisson Problem

    Hi, I know the weak form of the Poisson problem \nabla^2 \phi = -f looks like \int \nabla \phi \cdot \nabla v = \int f v for all suitable v. Is there a similarly well-known form for the slightly more complicated poisson problem? \nabla (\psi \nabla \phi ) = -f I am writing some finite...
  39. MarkFL

    MHB Solve Limit w/o L'Hôpital: Miras Tussupov's Q on Yaoo Answers

    Here is the question: I have posted a link there to this thread so the OP can view my work.
  40. R

    Form Factor and Neutron Scattering

    Hi all Can someone please describe how the form factor used in Rutherford scattering is applicable to neutron probing of nuclei? Also, is the kinetic energy required to probe a given radius simply given by the de Broglie wavelength where momentum, p >= h-bar / Radius ? (Relativity...
  41. M

    Form of Solution to Schrodinger Equation

    Hey guys, I just want to ask on how do you determine the form of wave function for Schrodinger equation of finite potential well and potential barrier. Why is it ψ(x) = Ae^ikx + Be^-ikx (x < -a) ψ(x) = Fe^ikx (x > a) ψ(x) = Ce^μx + De^-μx (-a < x < a) for k^2 =...
  42. TheDemx27

    C# C# Windows Form Game : Movement

    C# Windows Form "Game": Movement All I wanted to do was to make a block move right/left across the window. I'm using VS 2010. No compiler errors and when I run it, it doesn't respond to any input. using System; using System.Windows.Forms; namespace Game { public partial class Form1...
  43. polygamma

    MHB Show Integral of $f(z)$ with Exponential Form

    Show that $ \displaystyle \text{Im} \ \exp \left( ae^{be^{i c \ x}} \right) = \exp \left( ae^{b\cos(cx)\cos (b\sin cx)} \right) \sin \left( a\sin (b\sin c x) e^{b\cos cx} \right) $.EDIT: Then by integrating $ \displaystyle f(z) = \frac{z \exp ( ae^{be^{ic \ x}} )}{z^{2}+d^{2}}$ around a...
  44. J

    The one-loop correction in Lehmann-Kallen form

    Hi. I would like to ask a question about Chapter 15 in Srednicki's QFT book. In chapter 15, after eq. (15.12), he compares eq. (15.12) ## \mathrm{Im}\bm{\Delta}(k^2)=\frac{\mathrm{Im}\Pi (k^2)}{(k^2+m^2-\mathrm{Re}\Pi (k^2))^2 + (\mathrm{Im}\Pi (k^2))^2}## with eq. (15.8)...
  45. V

    Matrix form of Lie algebra highest weight representation

    I am currently working with Lie algebras and my research requires me to have matrix representations for any given Lie algebra and highest weight. I solved this problem with a program for cases where all weights in a representation have multiplicity 1 by finding how E_\alpha acts on each node of...
  46. D

    Which form of particle acceleration is safer?

    1. Linear or Circular Acceleration (Synchrotron) 2.I.e, which accelerator is safer in terms of radiation leakage and radiation outbreak. 3. I thought a Linac would be safer.
  47. B

    How much of the universe is in the form of electromagnetic radiation?

    Can you make an educated guess on the amount of energy in the universe in the form of electromagnetic radiation (photons), considering the vast amount of photons moving in every direction throughout the vast universe, there is literally no point in the universe that you can be in and not observe...
  48. L

    Approximation of values from non-closed form equation.

    Hello everyone, I'm working on a problem and it turns out that this equation crops up: 1 = cos^{2}(b)[1-(c-b)^{2}] where c > \pi Now I'm pretty sure you can't solve for b in closed form (at least I can't), so what I need to do is for some value of c, approximate the value of b to...
  49. N

    Why is a Kähler form not always holomorphic?

    Any Kähler form (?) can be written in local coordinates as \omega = \frac{i}{2} \sum h_{ij} dz^i \wedge d z^j with h_{ij}(z) = \delta_{ij} + \mathcal O(z^2). But that would mean \bar \partial \omega = \frac{i}{2} \sum \frac{\partial h_{ij}}{\partial \bar z_k} d \bar z^k \wedge dz^i \wedge d...
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