KVPY2012MathematicsEllipse
Consider the conic ex ²+ y²-2 e ² x -2 ² y + e ³+ ³= e . Suppose P is any point on the conic and S ₁, ~S ₂ are the foci of the conic, then the maximum value of ( PS ₁+ PS ₂ ) is -
Options
- Ae
- Be
- C2
- D2 e
Correct answer
C. 2
Step-by-step solution
e x²+ y²-2 e² x-2 ² y+e³+ ³= ee (x²-2 e x+e² )+ (y²-2 y+ ² )= e (x-e)² + (y- )² e =1a²= a= >eP S₁+P S₂=2 a Major axis is | to axis P S₁+P S₂=2 F