Is there a shortcut to summing Bessel functions with imaginary units?

Click For Summary
SUMMARY

The discussion focuses on summing the series \(\sum^{\infty}_{n=1}J_n(x)[i^n+(-1)^ni^{-n}]\), where \(i\) represents the imaginary unit. The user seeks a sophisticated solution without explicitly writing the Bessel functions. They identify that the terms can be simplified to \(2iJ_1(x) - 2J_2(x) + \ldots\) and propose splitting the series into sums of even and odd indices, which relate to known sums involving \(\sin(x)\) and \(J_0(x)\).

PREREQUISITES
  • Understanding of Bessel functions, specifically \(J_n(x)\)
  • Familiarity with complex numbers and the properties of the imaginary unit \(i\)
  • Knowledge of series summation techniques
  • Basic understanding of trigonometric functions and their relationships with Bessel functions
NEXT STEPS
  • Research the properties and applications of Bessel functions in mathematical physics
  • Learn about series convergence and techniques for summing infinite series
  • Explore the relationship between Bessel functions and trigonometric functions
  • Investigate advanced summation techniques for series involving complex numbers
USEFUL FOR

Mathematicians, physicists, and students studying applied mathematics, particularly those interested in series summation and Bessel functions.

matematikuvol
Messages
190
Reaction score
0

Homework Statement


What is easiest way to summate
[tex]\sum^{\infty}_{n=1}J_n(x)[i^n+(-1)^ni^{-n}][/tex]
where ##i## is imaginary unit.


Homework Equations





The Attempt at a Solution


I don't need to write explicit Bessel function so in sum could stay
[tex]C_1J_(x)+C_2J_2(x)+...[/tex]
Well I see that terms in the sum will be
[tex]2iJ_1(x)-2J_2(x)+...[/tex]
But I search for more sofisticated solution. Is there any way to sum this using ##i^1=i##,##i^2=-1##,##i^3=-i##,##i^4=1##?
 
Physics news on Phys.org
cute

first i^n+(-1)^n i^-n=2 i^n

then split into sums over

2k
2k+1

Which have nice well know sums involving sin(x) and J0(x)
 

Similar threads

Replies
8
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 2 ·
Replies
2
Views
4K
Replies
6
Views
4K
  • · Replies 3 ·
Replies
3
Views
3K