表达式4: "g" left parenthesis, "s" left parenthesis, "x" , right parenthesis , right parenthesisgsx
4
表达式5: StartRoot, "x" , EndRoot left brace, 0 less than or equal to "x" less than or equal to 1 , right bracex0≤x≤1
5
表达式6: 1 minus left parenthesis, "x" minus 1 , right parenthesis squared left brace, 0 less than or equal to "x" less than or equal to 1 , right brace1−x−120≤x≤1
6
表达式7: "x" left parenthesis, 2 minus "x" , right parenthesis left brace, 0 less than or equal to "x" less than or equal to 1 , right bracex2−x0≤x≤1
