# BESSELK

Formulas / BESSELK
Return the modified Bessel function.
`BESSELK(x,n)`
• x - the value to evaluate the function on
• n - the order of the Bessel function

## Examples

• `=BESSELK(x, 1)`

The BESSELK function returns the modified Bessel function with an order of 1 at a given point. This can be represented in the above formula, where x is the given point.

• `=BESSELK(x, 1)`

For example, if you wish to calculate the modified Bessel function at 1.5, you would enter the above formula into a cell. This would return a value of 0.4204004.

• `=BESSELK(1.5, 5)`

The BESSELK function can also be used to calculate the modified Bessel function with a different order than 1. For instance, this formula calculates the modified Bessel function with an order of 5 at 1.5.

• `=BESSELK(2.5, 1)`

The BESSELK function can also be used to calculate the modified Bessel function with a different point than 1.5. For example, if you wish to calculate the modified Bessel function with an order of 1 at 2.5, you would enter the formula above.

## Summary

The BESSELK function computes the modified Bessel function, which is the same as the Bessel function with purely imaginary arguments. It throws errors for non-numerical inputs and negative n values.

• The BESSELK function throws an error if either n or x are not numeric: #NUM! if n is negative and #VALUE! if x is not numeric.
• The BESSELK function calculates modified Bessel functions, which are Bessel functions with purely imaginary arguments.