HP 3000 Manuals

Compiler Library/XL Reference Manual

DTAN (or DTAN') 

DTAN calculates the tangent of a longreal number in radians.

Declaration 

        FUNCTION DTAN(VAR x:LONGREAL):LONGREAL; EXTERNAL;

Accuracy 


Attributes 

Parameter:                A longreal number in radians.

Result:                   A longreal number.

HP FORTRAN 77/XL:         Intrinsic function:  Y=DTAN(X).

Error:                    If the argument is a NaN, there are two
                          possible actions.  If the INVALID trap is
                          enabled, the message "DTAN(X): X=NaN" occurs.
                          Otherwise, the INVALID flag is set.  In either
                          case, a quiet NaN is returned.

                          When DABS(X) > 149078413.0, DTAN(X) completely
                          loses significance.  See Appendix A for more
                          details.

MPE/iX 5.0 Documentation