J3/06-  114r1

Subject: ATAN with two arguments works like ATAN2
From: David Muxworthy for /jor
References: J3-026

Revised Suggested edits (cf 06-114)

[294:27]    After "ATAN(X)" add "or ATAN(Y,X)"

[298:16+15] After "ATAN" in the first column in the table in 13.6, insert "(X)".

[305:28]    After "ATAN(X)" add " or ATAN(Y,X)"

[305:31-35] Change to read:

Arguments.
Y (optional) shall be of type real or complex.
X            shall be of type real or complex.
Result characteristics.  Same as X.
Result value.  If Y is present the result is the same as the result of ATAN2(Y,X).
               If Y is absent and X is real the result is expressed in radians and lies has a                value equal to a processor-dependent  approximation to arctan(X) that lies in
               the range -pi/2 .le. ATAN(X) .le. pi/2.
               If Y is abent and X is complex  the result is complex.  The real part                isexpressed in radians and lies in
                the range $-\frac\pi2 \leq$ REAL(ATAN(X)) $\leq \frac\pi2$."

Note to editor: these edits assume paper 05-204r2 has passed.