已知向量a=(sinθ,1),b=(1,cosθ),-π/2
问题描述：
已知向量a=(sinθ,1),b=(1,cosθ),-π/2
数学人气：271 ℃时间：2020-03-28 17:25:55
优质解答
a⊥b =>
a • b = (sinθ) * 1 + 1 * sinθ =0
=>
sinθ = cosθ
又 -π/2
a+b= ( sin(π/4) +1 ,1+cos(π/4))
|a+b|= √{[sin(π/4)+1]^2 + [1+cos(π/4)]^2}
= 1+√2
a • b = (sinθ) * 1 + 1 * sinθ =0
=>
sinθ = cosθ
又 -π/2
a+b= ( sin(π/4) +1 ,1+cos(π/4))
|a+b|= √{[sin(π/4)+1]^2 + [1+cos(π/4)]^2}
= 1+√2
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答
a⊥b =>
a • b = (sinθ) * 1 + 1 * sinθ =0
=>
sinθ = cosθ
又 -π/2
a+b= ( sin(π/4) +1 ,1+cos(π/4))
|a+b|= √{[sin(π/4)+1]^2 + [1+cos(π/4)]^2}
= 1+√2