BESSELI
Calculates the modified Bessel function of the first kind.
Syntax:
BESSELI(x, n)
returns the modified Bessel function of the first kind, of order n, evaluated at x.
The modified Bessel function of the first kind
where is the Bessel function of the first kind.
Example:
BESSELI(1, 1)
returns 0.565159103992.
