# BESSELI

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

If this function is not available, and returns the #NAME? error, install and load the Analysis ToolPak add-in.

2. In the Add-Ins available list, select the Analysis ToolPak box, and then click OK.
3. If necessary, follow the instructions in the setup program.

Syntax

BESSELI(x,n)

X     is the value at which to evaluate the function.

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

Remarks

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

Example

The example may be easier to understand if you copy it to a blank worksheet.

1. Create a blank workbook or worksheet.
2. Select the example in the Help topic.

Note   Do not select the row or column headers.

Selecting an example from Help
1. Press CTRL+C.
2. In the worksheet, select cell A1, and press CTRL+V.
3. To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
A B
Formula Description (Result)
=BESSELI(1.5, 1) Modified Bessel function at 1.5 with an order of 1 (0.981666)

Applies to:
Excel 2003