Question about parabolic cylinder functions

  • Context: Graduate 
  • Thread starter Thread starter PRB147
  • Start date Start date
  • Tags Tags
    Cylinder Functions
Click For Summary
SUMMARY

The discussion focuses on the interpretation of the expression for the parabolic cylinder function \( D_p(z) \) as presented in the 7th edition of "Table of Integrals, Series, and Products" by Gradshtyn and Ryzhik. Specifically, it clarifies that for negative values of \( x \), the argument \( \text{arg}(x^p) \) is defined as \( p\pi i \), leading to two possible definitions for \( x^p \): \( |x|^p e^{p\pi i} \) or \( |x|^p e^{-p\pi i} \). The consensus is to adopt the former definition for consistency in calculations. This clarification is essential for accurate application in mathematical contexts involving complex numbers.

PREREQUISITES
  • Understanding of complex analysis, specifically the concept of argument in complex numbers.
  • Familiarity with parabolic cylinder functions and their properties.
  • Knowledge of integral calculus, particularly improper integrals.
  • Experience with mathematical notation and expressions as used in advanced mathematics literature.
NEXT STEPS
  • Study the properties and applications of parabolic cylinder functions in mathematical physics.
  • Explore complex analysis topics, focusing on the argument and modulus of complex numbers.
  • Review integral calculus techniques, particularly those involving complex variables.
  • Examine the "Table of Integrals, Series, and Products" for further examples and applications of special functions.
USEFUL FOR

Mathematicians, physicists, and students in advanced mathematics courses who are dealing with complex functions and integrals, particularly those studying parabolic cylinder functions and their applications in various fields.

PRB147
Messages
122
Reaction score
0
In table of integrals, series and products 7ed. by Gradshtyn and Ryzhik,
in page 1028, there is an expression:
D_p(z)=\int_{-\infty}^{\infty}x^p e^{-2x^2+2i xz}dx,~~(Re~ p>-1; ~for~ x<0, ~arg x^p=p\pi i)

what is the meaning of for~ x<0, ~arg x^p=p\pi i)
 
Last edited:
Physics news on Phys.org
Hi PRB147! :smile:
PRB147 said:
In table of integrals, series and products 7ed. by Gradshtyn and Ryzhik,
in page 1028, there is an expression:
D_p(z)=\int_{-\infty}^{\infty}x^p e^{-2x^2+2i xz}dx,~~(Re~ p>-1; ~for~ x<0, ~arg x^p=p\pi i)

what is the meaning of for~ x<0, ~arg x^p=p\pi i)

if x is negative, then x = |x|e±πi

so xp could be defined as either |x|pepπi or |x|pe-pπi

the question is merely telling you to adopt the former definition! :wink:
 
thank you, tiny-tim!
I remember that arg(z) is a real number.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 12 ·
Replies
12
Views
4K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 14 ·
Replies
14
Views
2K