Oracle PL/SQL Tutorial/Numerical Math Functions/ATAN
ATAN(1)
<source lang="sql">
SQL> select ATAN(1) from dual;
ATAN(1)
.785398163</source>
ATAN(-1) (2)
<source lang="sql">
SQL> select ATAN(-1) from dual;
ATAN(-1)
-.78539816</source>
<source lang="sql">
SQL> select ATAN(1) from dual;
ATAN(1)
.785398163</source>
<source lang="sql">
SQL> select ATAN(-1) from dual;
ATAN(-1)
-.78539816</source>