Question

The sum of the focal distances of any point on the ellipse $9x^2+16y^2=144$ is

• A. 32
  
• B. 18
  
• C. 16
  
• D. 8

Answer 1

The correct option is D 8

$9x^2+16y^2=144$
$\Rightarrow \frac{x^2}{16}+\frac{y^2}{9}=1$
Here, a=4 and b=3
The sum of the foci distance of any point on an ellipse is constant and equal to the length 0. The length of the major axis of the ellipse. i.e., sum of the focal distance of any point on an ellipse.
$2\times 4=2a$