Question

请给出适当讲解和过程1.已知直线l：x-y+3=0及圆C：x2+(y-2)2=4,令圆C在x轴同侧移动,且与x轴相切.求

Answer 1

2.（1）由已知三距离成等差数列 |AF|-|BF|=|BF|-|CF| ,得：2*|BF|=|AF|+|CF| 2*9/5=[ (x1-4)^2 + y1^2 ]^(1/2) + [ (x2-4)^2 + y2^2 ]^(1/2)因为(x1,y1),(x2,y2)在圆上,x1^2/25+y1^2/9=1,x2^2/25+y2^2/9=1...