Report Issue

JEE MAIN 2021
16-03-2021 S2
Question
If the point of intersections of the ellipse $\frac{x^2}{16}+\frac{y^2}{b^2}=1$ 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 :
Select the correct option:
A
12
B
5
C
6
D
10
✓ Correct! Well done.
✗ Incorrect. Try again or view the solution.
Solution
$y^2=3 x^2$ and $x^2+y^2=4 b$ Solve both we get So $\mathrm{x}^2=\mathrm{b}$ $$ \frac{x^2}{16}+\frac{3 x^2}{b^2}=1, \frac{b}{16}+\frac{3}{b}=1 $$ $$ \begin{aligned} & b^2-16 b+48=0 \\ & (b-12)(b-4)=0 \\ & b=12, b>4 \end{aligned} $$
Question Tags
JEE Main
Mathematics
Easy
Start Preparing for JEE with Competishun