Oracle PL/SQL/Numeric Math Functions/ATAN
ATAN(-1)
SQL> --ATAN(x):Returns the arctangent of x.
SQL>
SQL>
SQL> select ATAN(-1) from dual;
ATAN(-1)
----------
-.78539816
SQL>
ATAN(x):Returns the arctangent of x
SQL> --ATAN(x):Returns the arctangent of x.
SQL>
SQL> select ATAN(1) from dual;
ATAN(1)
----------
.785398163
SQL>