Equation Icon  ∑n [ (1) (2) ] u(1)(t,x) + 𝜀u(2)(t,x) + ...= Aj (t + 𝜀t,x + 𝜀x) ∂u---(t,x) + 𝜀 ∂u--(t,x ) + ... t t 0 0 ∂xj ∂xj j=1 [ ] + B(t0 + 𝜀t,x0 + 𝜀x ) u(t0,x0) + 𝜀u(1)(t,x) + ... .