已知圓c1:x^2+y^2-2mx+4y+m^2-5=0,圓c2:x^2+y^2+2x-2my+m^2-3=0,m為何值時(1):… 已知圓c1:x^2+y^2-2mx+4y+m^2-5=0,圓c2:x^2+y^2+2x-2my+m^2-3=0,m為何值時(1):圓c1與圓c2相外切,並求此時內公切線的方程.(2)圓c1與圓c2內含

已知圓c1:x^2+y^2-2mx+4y+m^2-5=0,圓c2:x^2+y^2+2x-2my+m^2-3=0,m為何值時(1):… 已知圓c1:x^2+y^2-2mx+4y+m^2-5=0,圓c2:x^2+y^2+2x-2my+m^2-3=0,m為何值時(1):圓c1與圓c2相外切,並求此時內公切線的方程.(2)圓c1與圓c2內含

(1)圓1心(m,-2)R1=3,圓2心(-1,m)R2=2
(m+1)^2+(m+2)^2=25,
m=2或-5;
此時{x^2+y^2-4x+4y-1=0,x^2+y^2+2x-4y+1=0}
或{x^2+y^2+10x+4y+20=0,x^2+y^2+2x+10y+22=0}
得3x-4y+1=0
或4x-3y-1=0
(2)(m+1)^2+(m+2)^2=1,
m=-2或-1