Q.
Let C1 and C2 be two circles of radius r1 and r2 respectively (r1>r2) touching both the axes. If the two circles are orthogonal, then r2r1 is equal to
Let the equation of a circle touching both the axes be (x−r)2+(y−r)2=r2 x2+y2−2rx−2ry+r2=0
If the two given circles are orthogonal, then 2(−r1)(−r2)+2(−r1)(−r2)=r12+r22 ⇒r12−4r1r2+r22=0 ⇒r2r1=2+3