J1-func
This function returns the first order Bessel function:
J1(x)
The formula for the equation is:
See the gammaln(x) function for the definition of .
double J1(double x)
x
Returns the first order Bessel function at x.
aa = j1(5); aa =; //-0.32757913759147
J0, Jn, Y0, Y1, Yn,