# Search results

1. ### 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. ### A Question about computing residues after substitution

Hi, thank you very much for the answer Belgium 12
3. ### A Question about computing residues after substitution

Hi members, See attacged PDF file for my question Thank you
4. ### 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
5. ### 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
6. ### 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
7. ### I Laplace transform using differential equations

Hello Mark 44, If I understand it,Y'(0)=infinity.Here infinity can be treated as a constant. Thank you
8. ### 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...
9. ### Integrals log x in terms of dilogarithm

Hi members, see attached PdF file.Have you any idea to prove thes integrals Thank you
10. ### 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
11. ### 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
12. ### 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
13. ### 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
14. ### 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.
15. ### 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
16. ### 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
17. ### Fortran Hi,Below is a fortran program to calculate the roots of an

Fortran Hi, Thanks to Uart for his help.I changed the program with your suggestions and it works fine. Here is the program:! ! Numerical Mathematics and Computing, Fifth Edition ! Ward Cheney & David Kincaid ! Brooks/Cole Publ. Co. ! Copyright (c) 2003. All rights reserved. ! For...
18. ### 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...
19. ### 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...
20. ### 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
21. ### Complex variables

Hi, yes you are right. But it's my fault,I forgot something. I have to show this inequalities for z->infinity as a lower and upper bound in a complex integral. Sorry
22. ### 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
23. ### Laplace equation

It's to satisfy the boundary conditions at 0 and pi. solutions are u(x,y)=A exp(ny) + Bexp(-ny) or =a sinh(ny)+bcosh(ny) or =cosh(ny)+cosh n(y-pi) this satisfy thr BC at 0 and pi The laplace equation is invariant under translation belgium 12
24. ### 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...
25. ### LaTeX Use latex

HI, I start to understand the structure of latex.Icreated my first latex file with an editor. I runned latex on the tex file and I got dvi file.With preview I could see the text in ps or Pdf. It was a downloaded example. Now: 1)I run latex from from the prompt c:\ you click in...
26. ### LaTeX Use latex

Hi, thank you very much.I try it out.
27. ### LaTeX Use latex

use of latex hi, I have downloaded miktex 2.7(basic) and AMS latex. They are both installed,but how I start the two programs,and write math.expressions. I know maybe it is easy,but for me everything is new. Thanks for your help
28. ### 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...