# Homework Help: Bessel function

1. Dec 20, 2005

### asdf1

why does the v parameter in the bessel function
x^2y+xy`+(x^2-v^2)y=0 have to be real and nonegative?

2. Dec 20, 2005

### Tide

In the differential equation, there are no constraints on v (other than being finite) and solutions exist. If you want to call the solutions "standard Bessel functions" then the values of v are restricted. Generally, however, Bessel functions can have both complex arguments and indices.

3. Dec 23, 2005

### asdf1

thank you very much!