# Manuals/calci/BESSELY

BESSELY(x,n)

• is the value at which to evaluate the function
• is the integer which is the order of the Bessel Function
• BESSELY(), returns the Bessel Function Yn(x)

## Description

• This function gives the value of the modified Bessel function.
• Bessel functions is also called Cylinder Functions because they appear in the solution to Laplace's equation in cylindrical coordinates.
• Bessel's Differential Equation is defined as:

where is the arbitrary complex number.

• But in most of the cases is the non-negative real number.
• The solutions of this equation are called Bessel Functions of order .
• The Bessel function of the second kind and sometimes it is called Weber Function or the Neumann Function..
• The Bessel function of the 2nd kind of order can be expressed as:
• where is the Bessel functions of the first kind.
• This function will give the result as error when:
1.  or  is non numeric
2. , because  is the order of the function.


## ZOS

• The syntax is to calculate BESSELY in ZOS is .
• is the value at which to evaluate the function
• is the integer which is the order of the Bessel Function

## Examples

1. =BESSELY(2,3) = -1.1277837651220644
2. =BESSELY(0.7,4)= -132.6340573047033
3. =BESSELY(9,1) = 0.10431457495919716
4. =BESSELY(2,-1) = #N/A (ORDER OF FUNCTION < 0)

BESSEL Equation