方向微分
}
性質:
f ( v ) = f 1 ( v ) + f 2 ( v ) {\displaystyle f({\boldsymbol {v}})=f_{1}({\boldsymbol {v}})+f_{2}({\boldsymbol {v}})} なら、 ∂ f ∂ v ⋅ u = ( ∂ f 1 ∂ v + ∂ f 2 ∂ v ) ⋅ u {\displaystyle {\frac {\partial f}{\partial {\boldsymbol {v}}}}\cdot {\boldsymbol {u}}=\left({\frac {\partial f_{1}}{\partial {\boldsymbol {v}}}}+{\frac {\partial f_{2}}{\partial {\boldsymbol {v}}}}\right)\cdot {\boldsymbol {u}}} 。