Expression 33: "f" left parenthesis, "x" , "y" , right parenthesis equals "x" "y" StartRoot, max left parenthesis, 1 minus StartFraction, "x" squared Over "c" squared , EndFraction minus StartFraction, "y" squared Over "c" squared , EndFraction , 0 , right parenthesis , EndRootfx,y=xymax1−x2c21−y2c22,0