题目: Calculate the number of toys that land in each bin of a partitioned toy box. Mom and dad have a problem - their child John never puts his toys away when he is finished playing with them. They ga
叉积是向量的两种主要运算之一。我们设两个空间三维向量分别为 a = ( a x , a y , a z ) , b = ( b x , b y , b z ) \bm{a}=(a_x,a_y,a_z),b=(b_x,b_y,b_z) a=(ax,ay,az),b=(bx,by,bz)三维向量的叉积的两种定义分别为 c = a × b = ( a y b z − a z b y ,
一、向量叉积 两个向量 u u u、 v v v的叉积写作 u × v = n ∥ u ∥ ∥ v ∥ s i n θ \mathbf{u \times v = n \left \| u \right \| \left \| v \right \| sin\theta } u×v=n∥u∥∥v∥sinθ 式中, n n n: 与 u u u、 v v v均垂直的单位向量,theta是两向量的夹角