Question

Which of the following gives the equation of director circle of the ellipse $\frac{x^2}{25}+\frac{y^2}{16}=1$?

• A. x² - y² = 9
• B. x² + y² = 41
• C. x² + y² = 9
• D. x² + y² = 25

Answer 1

The correct option is B

x² + y² = 41

The equation of director circle of the ellipse $\frac{x^2}{a^2}+\frac{y^2}{b^2}=1is{x}^2+y^2=a^2+b^2$

$\Rightarrow Directorcircleof\frac{x^2}{25}+\frac{y^2}{16}=1is,$

$x^2+y^2=41$