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TS EAMCET · Maths · Circle

The lines represented by 5x2-xy-5x+y=0 are normals to a circle S=0. If this circle touches the circle S'x2+y2-2x+2y-7=0 externally, then the equation of the chord of contact of centre of S'=0 with respect to S=0 is

  1. A 2y-7=0
  2. B x-1=0
  3. C 3x+4y-7=0
  4. D x+y=5
Verified Solution

Answer & Solution

Correct Answer

(A) 2y-7=0

Step-by-step Solution

Detailed explanation

S'≡x2+y2-2x+2y-7=0 c1(-1,-1), r1 =1+1+7=3 Now a pair of lines 5x2-xy-5x+y=0 are normally to circle S=0 We know that normals of a circle intersect at centre To find the intersection point P=5x2-xy-5x+y=0 dPdx=10x-y-5=0 dPdy=-x+1=0 So x=1, y=5 c2(1, 5)…