Equation Icon  ∫ t Aˆ(t) = Aˆ(0)(t) + dt′χAx (t,t′)[F ˆ(t′) + G (t′)], ∫t0 (0) t ′ ′ ′ ˆB (t) = Bˆ (t) + dtχBF (t,t)xˆ(t), (126 ) t0