Equation Icon  P(τ,𝜃) = va(𝜃)τ + ϕ(𝜃) + u(τ,𝜃) (37 ) −2va(𝜃)τ Q(τ,𝜃) = q(𝜃) + e [ψ (𝜃) + w(τ,𝜃)], (38 )