表达式3: "f" left parenthesis, "z" , right parenthesis equals left parenthesis, "z" . "x" squared minus "z" . "y" squared plus "x" , negative 2 "z" . "x" "z" . "x" plus "y" squared plus "y" squared , right parenthesisfz=z.x2−z.y2+x,−2z.xz.x+y2+y2
3
表达式4: "D" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, "f" left parenthesis, left parenthesis, "x" , "y" , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis , right parenthesis less than or equal to 2Dffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffx,y≤2
