Expression 40: "N" Subscript, 1 , Baseline equals StartFraction, StartNestedFraction, 1 NestedOver "m" Subscript, 3 , Baseline , EndNestedFraction "M" Subscript, 1 , Baseline plus "M" Subscript, 2 , Baseline plus "m" Subscript, 3 , Baseline "T" Subscript, 1 , Baseline minus "T" Subscript, 2 , Baseline Over "m" Subscript, 3 , Baseline plus StartNestedFraction, 1 NestedOver "m" Subscript, 3 , Baseline , EndNestedFraction , EndFractionN1=1m3M1+M2+m3T1−T2m3+1m3