作OH⊥AB于H,设O到AB的距离为d,则 OH = d
由已知,∠B = 90° - 60° = 30°
在Rt△BOH中,OH=BO/2,即 d = x/2
当 d = x/2 < R = 2,即x < 4时,AB与圆O相交;
当 d = x/2 = R = 2,即x = 4时,AB与圆O相切;
当 d = x/2 > R = 2,即x > 4时,AB与圆O相离.
作OH⊥AB于H,设O到AB的距离为d,则 OH = d
由已知,∠B = 90° - 60° = 30°
在Rt△BOH中,OH=BO/2,即 d = x/2
当 d = x/2 < R = 2,即x < 4时,AB与圆O相交;
当 d = x/2 = R = 2,即x = 4时,AB与圆O相切;
当 d = x/2 > R = 2,即x > 4时,AB与圆O相离.