Search results

  1. B

    A Psi function or digamma function?

    Hi everyone, concerning serie representation of psi function. In te solution of bessel function of the second kind we have the following expressions for the psi functions psi(m+1) and psi(n+m+1) then they give the series for the two psi functions ie(or digamma function) sum k from 1 to m of...
  2. B

    A Question about computing residues after substitution

    Hi members, See attacged PDF file for my question Thank you
  3. B

    A Residues of gamma functions

    Hi members, I have a problem with the computation of residues involve the gamma functions. (see attached Pdf file) Can you show me for the first residue with the arrows, or give a hint or a link. Thank you
  4. B

    I Series expansions of log()

    Hi, see attached PdF file for my question concerning serie expansion of log(z) at infinity. Thank you Belgium 12
  5. B

    I Differentiation notation

    Hi members, see attached PdF file. What's the difference between d/dx and d/d(x^2) I don't understand this notation?? Thank You
  6. B

    I Laplace transform using differential equations

    Hi members, Laplace transform using differential equations.(see attached PDF file) My question d/ds(s^2 y- s Y(0)-Y'(0).)....... Y(t)=sin(sqrt(t)) Y(o)=0 Now Y'= cos(sqrt(t)/2sqrt(t) Y'(0)=infinity d/ds (Y'(0)=?? can it be treated as a constant or can we change limit and...
  7. B

    Integrals log x in terms of dilogarithm

    Hi members, see attached PdF file.Have you any idea to prove thes integrals Thank you
  8. B

    Substitution in integral

    Hi members, see attached Pdf file. For a<0,write b=-a and let x=bt.Then My question: how becomes the denominator x+a to 1-t??? I don't see it Thank you
  9. B

    Gamma function and factorial

    Hi members, gamma (n+1)=n! Now I have the following: gamma(2(n+3/2))=gamma(2n+1) What is factorial notation for this?? Thank you
  10. B

    To pwsnafu integral sinh^2(x/2)

    Hi dear members, Sorry for my mistake with coth(x/2). to pwsnafu:I want to integrate integral from -inf to +inf of 1/sinh^2(x/2) Thank you
  11. B

    Integral of 1/sinh^2(x/2)

    Hi dear members, I have a problem with the following integral: Integral 1/sinh^2(x/2) from -inf to +inf =-2 coth(x/2) must I consider it as a principal value integral??? Thank you
  12. B

    Summation with exponential functions

    Dear members, see attached pdf file.Can you help me to prove this formulas. Thank you Belgium 12 This is not homework.I'm 68 and retired.
  13. B

    Fourier transforms

    Hi members, I have a problem with fourier transforms. There are two attached Pdf files. My questions are on the Pdf files.Give me a little help. Thank you Belgium 12
  14. B

    Problem with two trigonometric integrals

    Hi I have a little problem with the integrals of the following functions. integral from 0to 2pi ∫sin^2(nθ+ψ)dθ=∫cos^2(nθ+ψ)dθ=pi ψ=the phase angle.They occur in the theory of vibrations. Is it appropriate to set ψ=0 Thank you
  15. B

    Fortran Hi,Below is a fortran program to calculate the roots of an

    Hi, Below is a fortran program to calculate the roots of an equation by newton's method. I compile the program with the free compiler g95: g95 -c newton.f95 then g95 newton.f95 -o newton.exe When I run the program newton.exe I get the error can't assign value INTENT(IN)::x to...
  16. B

    Zeros of bessel functions in scilab

    Hi, I use scilab 5.2.2 Ik have a problem to find the zeros or roots of the bessel functions J0,J1... Whel I write besselj(0,3) I get the value of the bessel function Jo(3)=0,2600520. Can someone help me how to find the zeros of these bessel functions in scilab. Thank you kind...
  17. B

    Ln(x) < sqrt(x) for 1<x<infinity

    Hi, How can I show or proof: 1) ln(x)<sqrt(x) for 1<x<infinity 2) ln(x)<1/sqrt(x) for 0<x<1 Thank you
  18. B

    Complex variables

    Hi, I need two simple proofs of complex inequalities. 1) |1-z|/|z|<2 2)|1+z|/|z|>1/2 Ik need them for a bound of a complex integral.It's not homework Thank you
  19. B

    Complex integral

    Hi, problrm with complex integral.Consider the integral \int_{0}^{\infty}\frac{(x^a-1)}{x^3-1}\,dx use the branch 0<phi<3pi/2 and an idented contour at z=0 and z=1.(circular contour in the upper half plane) a)show that the integral can be written in terms of the integral...
  20. B

    LaTeX Use latex

    Use of "Latex" Hi, I want to use Latex.I never heard about latex before. If it runs on my computer: 1)Where can I download the files I need. 2)How to install 3)Where can I find the source code for writing the mathematical expressions. My computer: O.S/:Windows...
  21. B

    Classification of quadrics

    Hi, can someone help me on a website for the classification of quadrics(ellipsoids,paraboloids,....) starting from the general second order equation. Thanks
  22. B

    Complex integral

    Hi, I have a problem with the following complex integral. Integral from 0 to+infinty sin²(a.lnz)/(x - 1)² = pi.a coth(2.pi.a) - 1/2 a>0 I tried different contours and methods,but without result. Can you help me to find out the complex contour integration. Thanks