Question

过点P(-2,3)作圆x^2+(y-1)^2=1的切线,切点分别为A,B,则AB的直线方程为_________

Answer 1

C:x^2+(y-1)^2=1.(1)

C(0,1),r=1

P(-2,3)

PA^2=PB^2=PC^2-r^2=7

P:(x+2)^2+(y-3)^2=7.(2)

(2)-(1):

AB:2x-2y+3=0