与向量a=(2,-1,2)共线且满足a*x=-18求向量x
问题描述:
与向量a=(2,-1,2)共线且满足a*x=-18求向量x
答
a*x=|a||x|cosθ =3*N*3*(-1)=-18
N=2
|x|=2|a|
x=(-4,2,-4)