JEE Main202116 Mar 2021Evening ShiftMathematicsEllipseActual
If the points of intersection of the ellipse x 2 16 + y 2 b 2 = 1 and the circle x 2 + y 2 = 4 b , b > 4 lie on the curve y 2 = 3 x 2 , then b is equal to :
Options
- A12
- B5
- C6
- D10
Correct answer
A. 12
Step-by-step solution
y 2 = 3 x 2 and x 2 + y 2 = 4 b Solving both the equations we get, x 2 = b As x 2 16 + y 2 b 2 = 1 ⇒ x 2 16 + 3 x 2 b 2 = 1 ⇒ b 16 + 3 b = 1 ⇒ b 2 - 16 b + 48 = 0 ⇒ b - 12 b - 4 = 0 ⇒ b = 12   ∵ b > 4