e=c/a=1/2
e=根(1-b2/a2)=1/2 b/a =根3/2
x1+x2=-b/a=-根3/2 x1x2=-c/a=-1/2
x1的平方+x2的平方=(x1+x2)的平方-2x1x2=3/4-2 (-1/2)=5/4>1
点P在圆外.