The Single UNIX ® Specification, Version 2
Copyright © 1997 The Open Group

 NAME

j0, j1, jn - Bessel functions of the first kind

 SYNOPSIS



#include <math.h>

double j0(double x);
double j1(double x);
double jn(int n, double x);

 DESCRIPTION

The j0(), j1() and jn() functions compute Bessel functions of x of the first kind of orders 0, 1 and n respectively.

An application wishing to check for error situations should set errno to 0 before calling j0(), j1() or jn(). If errno is non-zero on return, or the return value is NaN, an error has occurred.

 RETURN VALUE

Upon successful completion, j0(), j1() and jn() return the relevant Bessel value of x of the first kind.

If the x argument is too large in magnitude, 0 is returned and errno may be set to [ERANGE].

If x is NaN, NaN is returned and errno may be set to [EDOM].

If the correct result would cause underflow, 0 is returned and errno may be set to [ERANGE].

 ERRORS

The j0(), j1() and jn() functions may fail if:
[EDOM]
The value of x is NaN.
[ERANGE]
The value of x was too large in magnitude, or underflow occurred.

No other errors will occur.

 EXAMPLES

None.

 APPLICATION USAGE

None.

 FUTURE DIRECTIONS

None.

 SEE ALSO

isnan(), y0(), <math.h>.

DERIVATION

Derived from Issue 1 of the SVID.

UNIX ® is a registered Trademark of The Open Group.
Copyright © 1997 The Open Group
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