作业帮已知向量a=(sinθ,1),b=(1,cosθ),-π/2
来源：学生作业帮助网 编辑：作业帮 时间：2024/11/19 12:18:22
x){}KN?V83 CM$[
Cs;4ut7$铠a{i⣮I:66ۡ~O=@NBvRY-4<]i ;R 6\QPS022V
)@j*h)*hX@ * 6$ Fj L4
t !|Mol u̪63 (R _PF 1{ }ݟ
已知向量a=(sinθ,1),b=(1,cosθ),-π/2
已知向量a=(sinθ,1),b=(1,cosθ),-π/2<θ<π/2 (1)若a⊥b,求θ （2）求| a+b|的最大值
已知向量a=(sinθ,1),b=(1,cosθ),-π/2
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