向量a=(x,0),向量b=(1,y),(向量a+向量b)垂直(向量a-向量b).求x,y应满足的条件,写出x,y的取值范围
怎么做的?
过程!
参考答案:解:a+b=(x,0)+(1,y)=(x+1,y)
a-b=(x,0)-(1,y)=(x-1,-y)
∵a+b⊥a-b
∴(a+b).(a-b)
=x^2-1-y^2
=0
∴x^2-y^2=1
x^2=y^2+1≥1
∴x≥1,x≤-1
y^2=x^2+1≥1
∴y≥1,y≤-1
怎么做的?
过程!
参考答案:解:a+b=(x,0)+(1,y)=(x+1,y)
a-b=(x,0)-(1,y)=(x-1,-y)
∵a+b⊥a-b
∴(a+b).(a-b)
=x^2-1-y^2
=0
∴x^2-y^2=1
x^2=y^2+1≥1
∴x≥1,x≤-1
y^2=x^2+1≥1
∴y≥1,y≤-1