P=-4sinx
p^2=-4psinx
x^2+y^2=-4y
化简得
x^2+(y+2)^2=4 .(1)
Pcosx=1
x=1 .(2)
联立(1)(2)得,
x1=1 y1=√3-2
x2=1 y2=-√3-2
∴A(1,√3-2)
B(1,-√3-2)
|AB|=√(1-1)^2+[-√3-2-(√3-2)]^2
=2√3