If P x 1 , y 1 is a point such that the lengths of the tangents from it to the circles x 2 + y 2 - 4 x - 6 y…

If Px1,y1 is a point such that the lengths of the tangents from it to the circles x2+y2-4x-6y-12=0 and x2+y2+6x+18y+26=0 are in the ratio 2:3, then the locus of P is
  1. x2+y2+24x-36y+62=0
  2. x2+y2-12x-1265y-2125=0
  3. x2+y2-24x-54y-88=0
  4. x2+y2+24x+36y+62=0

Solution

Given:

C1x2+y2-4x-6y-12=0

C2x2+y2+6x+18y+26=0

Now, we know that length of tangent drawn from any point to circle is given by S1.

Now, it is given that, S1S2=23

S1S2=49

9S1-4S2=0

9h2+k2-4h-6k-12-4h2+k2+6h+18k+26=0

5h2+5k2-60h-126k-212=0

h2+k2-12h-1265k-2125=0

Therefore, locus is

x2+y2-12x-1265y-2125=0.

Asked in: AP EAMCET 2018 (25 Apr Shift 1)

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