Calculation: 1ROa8w - 1

α  = 
 
 Δ_l
/ ( l_1* Δ_t)
α =  
 Δ_l
/ ( l_1* Δ_t)
$$\alpha$$ = $$\frac{\Delta_{l}}{l_{1}\cdot \Delta_{t}}$$
α =  
 Δ_l
/ l_1/ Δ_t
$$\alpha$$ = $$\frac{\Delta_{l}}{l_{1}\cdot \Delta_{t}}$$