表达式17: left parenthesis, "x" Subscript, 2 , Baseline , "y" Subscript, 2 , Baseline , right parenthesis , left parenthesis, "A" Subscript, 1 , Baseline , "A" Subscript, 2 , Baseline "L" Subscript, "i" "m" , Baseline , right parenthesisx2,y2,A1,A2Lim
17
表达式18: left parenthesis, "x" Subscript, 1 , Baseline , "y" Subscript, 1 , Baseline , right parenthesis , left parenthesis, "x" Subscript, 4 , Baseline , "y" Subscript, 4 , Baseline "L" Subscript, "i" "m" , Baseline , right parenthesisx1,y1,x4,y4Lim
18
表达式19: left parenthesis, "x" Subscript, 3 , Baseline , "y" Subscript, 3 , Baseline , right parenthesis , left parenthesis, "x" Subscript, 2 , Baseline , "y" Subscript, 2 , Baseline "L" Subscript, "i" "m" , Baseline , right parenthesisx3,y3,x2,y2Lim
19
表达式20: left parenthesis, "A" Subscript, 1 , Baseline , "A" Subscript, 2 , Baseline plus left parenthesis, "y" Subscript, 4 , Baseline minus "A" Subscript, 2 , Baseline , right parenthesis "t" "L" Subscript, "i" "m" , Baseline , right parenthesisA1,A2+y4−A2tLim
