2. Inverse application of the total differential rule R<。b-小 Op4 Varl、Op2 Op5 Op3 Var2 Qp4xOp2+05×p3=Op2. Inverse application of the total differential rule u v ⎯Op1 ⎯ Var1 Var2 u v Op4 Op2 Op5 Op3 Op4Op2 + Op5Op3 = Op1