設(shè)點(diǎn)(sinθ,cosθ)到直線xcosθ+ysinθ+1=0的距離小于1/2,則θ的取值范圍是____________
設(shè)點(diǎn)(sinθ,cosθ)到直線xcosθ+ysinθ+1=0的距離小于1/2,則θ的取值范圍是____________
求詳解,我會(huì)追加分?jǐn)?shù).
優(yōu)質(zhì)解答
|sinθcosθ+sinθcosθ+1|<1/2
|1+siin2θ|<1/2
-1/2<1+sin2θ<1/2
-3/2-1≤sin2θ<-1/2
2kπ-5π/6≤2θ<2kπ-π/6
kπ-5π/12≤θ