Bessel functions, named after
Friedrich Bessel, are solutions
y(
x) of "Bessel's
differential equation"
- x2y'' + xy' + (x2 - n2)y = 0
for non-negative integer values of n.
They come in two kinds:
- Bessel functions of the first kind Jn(x), the solutions of the above differential equation which are defined for x = 0.
- Bessel functions of the second kind Yn(x), the solutions which are non-singular (infinite) for x = 0.
They are important in many physical problems including those involving spherical or cylindrical? coordinates, and in frequency modulation.
Applications: