The BESSELI function returns the modified Bessel function In (x), which is equivalent to the Bessel function evaluated for purely imaginary arguments.

**Syntax**: BESSELI( x, n )

The BESSELI function syntax has the following arguments:

**X**Required. The value at which to evaluate the function.-
**N**Required. The order of the Bessel function. If n is not an integer, it is truncated.

**Example**: Let’s look at some Excel BESSELI function examples and explore how to use the BESSELI function as a worksheet function in Microsoft Excel:

**Syntax**: =BESSELI(A2,B2)

**Result**:

Based on the Excel spreadsheet above, the following BESSELI examples would return:

**Syntax**: =BESSELI(A3,B3)

**Result**: 2.516716242

**Syntax**: =BESSELI(A4,B4)

**Result**: 0.565159098

**Syntax**: =BESSELI(A5,B5)

**Result**: 1.590636857

**Syntax**: =BESSELI(A6,B6)

**Result**: 1.590636857

**Syntax**: =BESSELI(A7,B7)

**Result**: 0.688948449

**Syntax**: =BESSELI(A8,B8)

**Result**: 0.981666428

**Syntax**: =BESSELI(A9,B9)

**Result**: -0.981666428

**Syntax**: =BESSELI(A10,B10)

**Result**: #NUM!

**Note**:

- 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: