Isentropic Flow Relation Density Formula

Equation for calculate isentropic flow relation density is,

ρ / ρ_t = (1 + ((γ - 1) / 2) x M²)^{(-1 / (γ - 1))}

Where,
ρ / ρ_t =Isentropic Flow Relation Between Density and Total Density
ρ = Density
ρ_t = Total Density
γ = Specific Heat Ratio
M = Mach Number