圓心到直線(xiàn)的距離
d=|0-m*0+2|/根號(hào)(1^2+(-m)^2)=2/根號(hào)(m^2+1)
d不會(huì)為0,直線(xiàn)不經(jīng)過(guò)圓心.
當(dāng)d
則當(dāng)m<-根號(hào)3,或者m>根號(hào)3時(shí),直線(xiàn)和圓相交.
當(dāng)d=r時(shí),2=根號(hào)(1+m^2).則當(dāng)m=±根號(hào)3時(shí),圓和直線(xiàn)相切.
當(dāng)d>r時(shí),即2>根號(hào)(1+m^2).化簡(jiǎn)得m^2<3.
則當(dāng)-根號(hào)3