表达式4: StartFraction, 2.0 "n" "f" Over ( "f" plus "n" minus "z" Subscript, "n" 11 , Baseline ( "f" minus "n" ) ) , EndFraction2.0nf(f+n−zn11(f−n))
equals=
11
4
表达式5: "z" Subscript, "n" 01 , Baseline equals 0zn01=0
00
11
5
表达式6: StartFraction, "f" "n" Over "z" Subscript, "n" 01 , Baseline left parenthesis, "n" minus "f" , right parenthesis plus "f" , EndFractionfnzn01n−f+f
equals=
11
6
表达式7: StartFraction, "f" "n" Over "z" Subscript, "n" 01 , Baseline left parenthesis, "f" minus "n" , right parenthesis plus "n" , EndFractionfnzn01f−n+n
