3 設a為常數向量(constant vector), ,下列何者錯誤? (A)∇ ∙ r= 3 (B)∇ ∙ (a ×r ) = 0 (C)∇ × r= 0 (D)∇ × (a×r ) =a
3 設a為常數向量(constant vector), ,下列何者錯誤? (A..-阿摩線上測驗