Musical instruments that start with the letter I include the igil, ipu, Irish uillean, Irish bouzouki, ichigenkin, inci, iya, itotele and istarski mih. The instruments originate from countries ranging from Cuba and Ireland to Croatia, Japan and the Philippines.
Bessel's functions are often used in acoustics for describing circular membranes behaviour (exploited by most of the musical instruments). They are the solutions of the wave equations using polar coordinates. Set the properties of the membrane Bessel's functions describe the vibrational modes of the membrane.
BESSELJ(X, N) The BESSELJ 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. If x is nonnumeric, BESSELJ returns the #VALUE! error value. If n is nonnumeric, BESSELJ returns the #VALUE! error value. If n < 0, BESSELJ returns the #NUM! error value. The n-th order Bessel function of the variable x is: where: is the Gamma function.