表达式3: left parenthesis, StartFraction, "d" Over "d" "a" , EndFraction "f" left parenthesis, "a" , right parenthesis , right parenthesis left parenthesis, "x" minus "a" , right parenthesis plus "f" left parenthesis, "a" , right parenthesis equals "y"ddafax−a+fa=y
3
表达式4: "a" equals negative 0.3 9a=−0.39
4
表达式5: "b" equals "f" left parenthesis, "a" , right parenthesisb=fa
5
表达式6: left parenthesis, StartFraction, "d" Over "d" "a" , EndFraction "f" left parenthesis, "a" , right parenthesis , right parenthesis equals "m"ddafa=m
