Question

设集合A={(x,y)\x^2+y^2=1},集合B={(x,y)\x^2+x-y+3=0},集合C={(x,y)\y=

Answer 1

A：为单位圆

B：y=x^2+x+3为抛物线

C：y=mx+n为直线

A ∩C为空集,表明圆心到直线的距离大于半径,即|n|/√(m^2+1)>1,即n^2>m^2+1,对于N,则有：n>m

B ∩C为空集,表明mx+n=x^2+x+3没实数根,即x^2+(1-m)x+3-n=0无实根,即delta=(1-m)^2-4(3-n)(m-1)^2,由此则有：n