Expression 43: "F" Subscript, 1 , Baseline equals StartFraction, "B" Subscript, 2 , Baseline plus StartNestedFraction, 1 NestedOver "m" Subscript, 2 , Baseline , EndNestedFraction "M" Subscript, 1 , Baseline plus "M" Subscript, 2 , Baseline minus "m" Subscript, 2 , Baseline "B" Subscript, 1 , Baseline Over "m" Subscript, 2 , Baseline plus StartNestedFraction, 1 NestedOver "m" Subscript, 2 , Baseline , EndNestedFraction , EndFractionF1=B2+1m2M1+M2−m2B1m2+1m2