Calculation: 1nRmlk - 1

V_2  = 
 V_1* (1+ β* Δ_t)
V_2 =  V_1* (1+ β* Δ_t)$$V_{2}$$ = $$V_{1}\cdot (1+\beta\cdot \Delta_{t})$$
V_2 = V_1+ Δ_t* β* V_1$$V_{2}$$ = $$V_{1}+\Delta_{t}\cdot \beta\cdot V_{1}$$
V_2 = V_1+ V_1* Δ_t* β$$V_{2}$$ = $$V_{1}+V_{1}\cdot \Delta_{t}\cdot \beta$$