• ← BesselJZero
• → BesselY

BesselK

Modified Bessel function of the second kind (SymPy, WMA)

BesselK[n, z]

returns the modified Bessel function of the second kind $K_n(z)$.

• • BesselK[1.5, 4]

• • Plot[BesselK[0, x], {x, 0, 5}]

The special case of half-integer index is expanded using Rayleigh's formulas:

• • BesselK[-3/2, x]