设平面内有四个向量a,b,x,y,满足a=y-x,b=2x-y,a⊥b,a的绝对值=b的绝对值=1 (1)|x|,|y|
问题描述:
设平面内有四个向量a,b,x,y,满足a=y-x,b=2x-y,a⊥b,a的绝对值=b的绝对值=1 (1)|x|,|y|
答
(y-x)(2x-y)=0
(y-x)^2=1
(2x-y)^2=1
(y-x+(2x-y))^2=1+1+0=2
x^2=2
|x|=sqrt(2)
(2(y-x)+(2x-y))^2=4+1+0=5
y^2=5
|y|=sqrt(5)