NTA Abhyas JEE Main2020MathematicsStraight LinesPractice
The area (in sq. units) of the locus of the point at which the two circles x 2 + y 2 = 1 and x - 4 2 + y 2 = 4 subtend equal angles is
Options
- A32 9 π
- B32 3 π
- C64 3 π
- D64 9 π
Correct answer
D. 64 9 π
Step-by-step solution
sin ⁡ θ = 1 h 2 + k 2 = 2 h - 4 2 + k 2 ⇒ h 2 - 8 h + 16 + k 2 = 4 h 2 + 4 k 2 ⇒ 3 x 2 + 3 y 2 + 8 x - 16 = 0 Radius of the circle is 4 3 2 + 16 3 = 8 3 units Hence, the area of the circle is equal to 64 π 9 sq. units