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AP EAMCET · Maths · Circle

If the line through the point \(P(5,3)\) meets the circle \(x^2+y^2-2 x-4 y+\alpha=0\) at \(\mathrm{A}(4,2)\) and \(\mathrm{B}\left(x_1, y_1\right)\), then \(P A \cdot P B\) is equal to

  1. A 6
  2. B 12
  3. C 9
  4. D 8
Verified Solution

Answer & Solution

Correct Answer

(D) 8

Step-by-step Solution

Detailed explanation

Line through \(P(5,3)\) meets the circle \(x^2+y^2-2 x-4 y+\alpha=0 \text { at } A(4,2) \text { and } B\left(x_1, y_1\right)\) \(\therefore A(4,2)\) lies on the circle \(\Rightarrow 16+4-8-8+\alpha=0 \Rightarrow \alpha=-4\) Eq. of circle becomes \(x^2+y^2-2 x-4 y-4=0\) Also,…
From AP EAMCET
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