Question

Tangents PA and PB are drawn to circle (x + 4)² + (y – 4)² =1 from variable points P on xy = 1. The locus of circumcentre of the triangle PAB is:

• A. (2x – 4) (2y – 4) = 1
• B. (2x + 4) (2y – 4) = 1
• C. (2x + 4) (2y + 4) = 1
• D. None of these

Answer 1

Answer: (B)

(2x + 4) (2y – 4) = 1

Answer 2

Locus is mid-point of P and centre of circle

Ž x = $\frac{- 4 + t}{2}$

y = $\frac{4 + \frac{1}{t}}{2}$

Ž (2x + 4) (2y – 4) = 1