C1 and C2 are the external and internal centres of similitude of the circles x2+y2−2x+4y+1=0 and x2+y2+4x−6y+12=0. If the radius of the circle having C1C2 as its diameters is r then
C1 and C2 are external and internal similitude of the circle x2+y2−2x+4y+1=0 and ‌‌x2+y2+4x−6y+12=0 Centre of circle x2+y2−2x+4y+1=0 is (1,−2),r1=2 Centre of circle x2+y2+4x−6y+4=0 (−2,3),r2=1 Coordinate of C1=‌