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AP EAMCET · Maths · Circle

If the angle between the tangents drawn to the circle \(x^2+y^2-12 x-16 y=0\) at the points where the line \(5 y=5 x+k\) cut the circle is \(60^{\circ}\), then the value of \(k\) is

  1. A \(5+\sqrt{2}\)
  2. B \(5(2 \pm 5 \sqrt{2})\)
  3. C \(2 \pm 5 \sqrt{2}\)
  4. D \(5 \pm 5 \sqrt{2}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(5(2 \pm 5 \sqrt{2})\)

Step-by-step Solution

Detailed explanation

Let the point \(P\left(x_1, y_1\right)\), then \[ \frac{10}{\sqrt{x_1^2+y_1^2-12 x_1-16 y_1}}=\frac{1}{\sqrt{3}} \] \(\Rightarrow \quad x_1^2+y_1^2-12 x_1-16 y_1=300\) Since, line \(A B, 5 y=5 x+k\), is a chord of contact of circle with respect to point…