Calculation: WpXAe4 - 1

 
 sin(α)
/ sin(γ)
  = 
n
 
 sin(α)
/ sin(γ)
 = n$$\frac{sin(\alpha)}{sin(\gamma)}$$ = $$n$$
sin(α) =  n* sin(γ)$$sin(\alpha)$$ = $$n\cdot sin(\gamma)$$
α = arcsin( n* sin(γ))$$\alpha$$ = $$arcsin(n\cdot sin(\gamma))$$