2 \mu_A(t + 1) - 2 \mu_A(t) & = T E(t + 1) + T E(t) \\
  2 \mu_A(t) - 2 \mu_A(t - 1) & = T E(t) + T E(t - 1) \\
   \mu_A(t) & = \frac{T E(t) + T E(t - 1) + 2 \mu_A(t - 1)}{2} \\
   \mu_A(t) & = \frac{T (E(t) + E(t - 1)) + 2 \mu_A(t - 1)}{2}