Question

空间法向量与z轴垂直,隐含条件?

Answer 1

向量c与z轴垂直,c= (x.y.0)

cXa=5y+x-5x-3y

=-4x+2y=9---------------------(1)

cXb=-3y+2x+3x-y=5x-4y=-4------------(2)

2*(1)+(2),

-3x=14

x=-14/3

y=(1/2)*(9+4x)=-29/6

c=(-14/3.-29/6.0)