(4)$ \帽子u = \压裂{- g (i \ω)\ partial_x \ h +帽子fg \ partial_y \帽子h} {f²+ (i \ω)²}$$ \帽子u = \压裂{- g (i \ω)h fg \ partial_y \ \ partial_x \帽子帽子h} {f²+ (i \ω)²}$
(4)$ \帽子u = \压裂{- g (i \ω)\ partial_x \ h +帽子fg \ partial_y \帽子h} {f²+ (i \ω)²}$
(4)$ \帽子u = \压裂{- g (i \ω)h fg \ partial_y \ \ partial_x \帽子帽子h} {f²+ (i \ω)²}$