# The Excel BESSELJ Function

## Basic Description

The Excel Besselj function returns the Bessel function, Jn(x), for a specified order and a given value of x.

The syntax of the function is :

BESSELJ( x, n )

where the function arguments are:

 x - The value at which the function is to be evaluated n - The order of the Bessel function (must be a positive integer)(If the supplied value of n is a decimal, Excel truncates this value to an integer)

## Besselj Function Example

Order 1, 2 & 3 Bessel Functions, Jn(x)

The above chart on the right shows the Bessel functions, Jn(x), of order 1, 2 and 3.

The value of any of these functions at a given value of x, can be evaluated using the Excel Besselj function.

For example, the order 1 Bessel function, at x=2.5 is calculated by the following:

=BESSELJ( 2.5, 1 )

This gives the result 0.497094103.

Further examples of the Excel Besselj function can be found on the Microsoft Office website.

## Besselj Function Errors

If you get an error from the Excel Besselj function, this is likely to be one of the following :

Common Errors
 #NUM! - Occurs if the supplied value of n is < 0 #VALUE! - Occurs if any of the supplied arguments are non-numeric #NAME? - Occurs when Analysis ToolPak add-in is not enabled in your Excel. You will need to enable the add-in if you want to use the Excel engineering functions.