BesselJ(n,x)
BesselJ_n x
i1 : BesselJ_0 .5 o1 = .938469807240813 o1 : RR (of precision 53)
i2 : BesselJ_2 3p200 o2 = .486091260585891076907831094114984034801662265643298727377034 o2 : RR (of precision 200)
See Bessel function.
The object BesselJ is a method function.