NTA Abhyas JEE Main2020MathematicsEllipsePractice
If the tangents P Q and P R are drawn from a variable point P to the ellipse x 2 16 + y 2 9 = 1 , such that the fourth point S of the parallelogram P Q S R lies on the circumcircle of the Δ P Q R , then the area (in sq. units) of the locus of P is
Options
- A7 π
- B16 π
- C25 π
- D9 π
Correct answer
C. 25 π
Step-by-step solution
Parallelogram P Q S R is a cyclic quadrilateral ⇒ Parallelogram is a rectangle ⇒ ∠ Q P R = 90 o Let, the equation of the tangent from P h , k to the ellipse is y = m x ± 16 m 2 + 9 ⇒ k - m h 2 = 16 m 2 + 9 ∵ m 1 m 2 = - 1 ⇒ h 2 - 16 = - k 2 + 9 ⇒ locus of P is x 2 + y 2 = 25 Hence, the area of locus of P is 25 π sq. units