Question

直线l截圆x^2+y^2-2y=0所得弦AB的中点（-1/2,3/2),则AB=

Answer 1

x^2+y^2-2y=0

x^2+(y-1)^2=1

圆心到AB中点的距离d=√[(0+1/2)^2+(1-3/2)^2]=√2/2

AB=2√(r^2-d^2)=2√(1-1/2)=√2