Legendre Definition and 224 Threads

  1. I

    How Do You Derive the Formula for P-n(0) Using Legendre Polynomials?

    There is a question where you should find a formula for P-n(0) using the Legendre polynomials: P-n(x)=1/(2^n*n!) d^n/dx^n(x^2-1)^n , n=0,1,2,3... I tried to derive seven times by only substituting the n until n=7,I did that because i wanted to find something that i can build my formula but i...
  2. L

    The Legendre Transform for Hamiltonians?

    I'm trying to implement and extend the work of Emmanuel Prados (http://www-sop.inria.fr/odyssee/research/prados-faugeras:04b/thesis.htm). I'm trying to follow how Appendix A, "How to transform a convex Hamiltonian into a HJB Hamiltonian; Legendre Transform", works for the provided example. I've...
  3. N

    Legendre polynomial integration

    Homework Statement int x^m*P_n(x) dx=0 where integration is from (-1) to (+1).Given m<n Homework Equations The Attempt at a Solution I took integrand F(x) and saw that F(-x)=(-1)^(m+n)*F(x) should that help anyway?
  4. N

    How to Prove Properties of Legendre Polynomials?

    Homework Statement I am to prove that P_n(-x)=(-1)^n*P_n(x) And, P'_n(-x)=(-1)^(n+1)*P'_n(x) Homework Equations The Attempt at a Solution I know that whether a Legendre Polynomial is an even or odd function depends on its degree.It follows directly from the solution of...
  5. B

    Contour Integration with Legendre Functions

    Homework Statement P_n (z) and Q_n (z) are Legendre functions of the first and second kinds, respectively. The function f is a polynomial in z. Show that Q_n (z) = \frac{1}{2} P_n (z) \ln \left(\frac{z+1}{z-1} \right) + f_{n-1} (z) implies Q_n (z) = \frac{1}{2} \int \frac{P_n (t) \...
  6. A

    Struggling with Legendre Polynomials: Any Suggestions?

    Hello everyone i had some questions about legendre polynomials. I have solved most of them but i had just two not answered question. I tried to solve this problem by rodriguez rule but it was really hard for me. Could anyone help me or give me some hints for this question...
  7. A

    Legendre polynomials proof question.Help

    Hello everyone i had some questions about legendre polynomials. I have solved most of them but i had just two not answered question. I tried to solve this problem by rodriguez rule but it was really hard for me. Could anyone help me or give me some hints for this question...
  8. A

    Legendre poynomials proof question.Help

    Hello everyone i had some questions about legendre polynomials. I have solved most of them but i had just two not answered question. I tried to solve this problem by rodriguez rule but it was really hard for me. Could anyone help me or give me some hints for this question...
  9. S

    Proving Orthogonality of Legendre Polynomials P3 and P1

    To show that two Legendre polynomials(Pn and Pm) are orthogonal wht is the test that i have to use? is it this? \int_{-1}^{1} P_{n}(x)P_{m}(x) dx = 0 in that case to prove that P3 and P1 are orthogonal i have to use the above formula??
  10. L

    Expand a function in terms of Legendre polynomials

    Problem: Suppose we wish to expand a function defined on the interval (a,b) in terms of Legendre polynomials. Show that the transformation u = (2x-a-b)/(b-a) maps the function onto the interval (-1,1). How do I even start working with this? I haven't got a clue...
  11. L

    Proving Orthogonality of Legendre Polynomials

    Problem: Show that \int_{-1}^{1} x P_n(x) P_m(x) dx = \frac{2(n+1)}{(2n+1)(2n+3)}\delta_{m,n+1} + \frac{2n}{(2n+1)(2n-1)}\delta_{m,n-1} I guess I should use orthogonality with the Legendre polynomials, but if I integrate by parts to get rid of the x my integral equals zero. Any tip on...
  12. G

    Solution of hydrogen atom : legendre polynomials

    I was messing around with the \theta equation of hydrogen atom. OK, the equation is a Legendre differential equation, which has solutions of Legendre polynomials. I haven't studied them before, so I decided to take closed look and began working on the most simple type of Legendre DE. And the...
  13. G

    Legendre Polynomials Orthogonality Relation

    ...and orthogonality relation. The book says \int_{-1}^{1} P_n(x) P_m(x) dx = \delta_{mn} \frac{2}{2n+1} So I sat and tried derieving it. First, I gather an inventory that might be useful: (1-x^2)P_n''(x) - 2xP_n'(x) + n(n+1) = 0 [(1-x^2)P_n'(x)]' = -n(n+1)P_n(x) P_n(-x) = (-1)^n P_n(x)...
  14. E

    How is the Legendre transform defined in cases where g(p) equals 0?

    Legendre transform... If we define a function f(r) with r=x,y,z,... and its Legnedre transform g(p) with p=p_x ,p_y,p_z,... then we would have the equality: Df(r)=(Dg(p))^{-1} (1) where D is a differential operator..the problem is..what happens when g(p)=0?...(this problem is...
  15. R

    Legendre polynomials application

    I need some help. I fitted a 7th order legendre polynomial and got the L0 to L7 coefficients for different ANOVA classes. How can I get a back transformation in order to plot each class using the estimated coefficients? Thanks to anybody. Roberto.
  16. W

    Back Transformation for Legendre Polynomials

    some body who can explain for me the Legndre polynomials:eek: :eek:
  17. M

    Proof of orthogonality of associated Legendre polynomial

    Hi, I'm trying to prove the orthogonality of associated Legendre polynomial which is called to "be easily proved": Let P_l^m(x) = (-1)^m(1-x^2)^{m/2} \frac{d^m} {dx^m} P_l(x) = \frac{(-1)^m}{2^l l!} (1-x^2)^{m/2} \frac {d^{l+m}} {dx^{l+m}} (x^2-1)^l And prove \int_{-1}^1...
  18. A

    Is the legendre equation an example of a frobenius equation?

    is the legendre equation an example of a frobenius equation?
  19. A

    Legendre Polynomial: Understanding the Basics

    can someone explain step-by-step why the legendre polynomial came into being? I'm having one hard time understanding it...
  20. T

    Find Legendre Polynomials of Order 15+

    Hey there, does anyone know where I could find a list of Legendre Polynomials? I need them of the order 15 and above, and I haven't been able to find them on the net. Thanks!
  21. H

    How Do You Derive the Second Solution for Legendre Polynomials?

    Hi, I have a problem where I am given the Legendre equation and have been told 1 solution is u(x). It asks me to obtain an expression for the second solution v(x) corresponding to the same value of l. I think it requires Sturm Liouville treatment but don't have a clue how to begin. Please HELP!
  22. A

    Legendre equation and angular momentum

    Hi all, I've been doing a math problem about the Legendre differential equation, and finding there are two linearly independent solutions. When I was taught about quantum mechanics the polynomial solutions were introduced to me as the basis for spherical harmonics and consequently the...
  23. A

    Legendre symbol proof for (-5/p)

    I am working on some homework that I already handed in, but I can't get one of the problems. The fourth problem on the HW was to prove the forms of (-1/p), (2/p), (3/p), (-5/p), and (7/p). I did this for -1 and 2 using the quadratic residues and generalizing a form for them. for 3 and 7 i...
  24. T

    Legendre Polynomials: Beginner's Guide

    hi folks! I have been trying to figure out some plausible geometric intrepretation to legendre polynomials and what are they meant to do. I have come across the concept of orthogonal polynomials while working with some boundary value problems in solid mechanics and wasn't able to come to...
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