BESSELK

Returns the modified Bessel function, which is equivalent to the Bessel functions evaluated for purely imaginary arguments.

If this function is not available, run the Setup program to install the Analysis ToolPak. After you install the Analysis ToolPak, you must enable it by using the Add-Ins command on the Tools menu.

Syntax

BESSELK(x,n)

X   is the value at which to evaluate the function.

N   is the order of the function. If n is not an integer, it is truncated.

Remarks

• If x is nonnumeric, BESSELK returns the #VALUE! error value.
• If n is nonnumeric, BESSELK returns the #VALUE! error value.
• If n < 0, BESSELK returns the #NUM! error value.
• The n-th order modified Bessel function of the variable x is:

  

  where J_n and Y_n are the J and Y Bessel functions, respectively.

Example

BESSELK(1.5, 1) equals 0.277388