Question

If $x^2+\lambda y^2=20$ represents an ellipse , then

• A. $\lambda >1$
• B. $\lambda <1$
• C. $\lambda >0$
• D. None of these

Answer 1

The correct option is C $\lambda >0$

$x^2+\lambda y^2=20$

$\Rightarrow \frac{x^2}{20}+\frac{\lambda y^2}{20}=1.....\left(1\right)$

For equation $\left(1\right)$ to represent ellipse,

$\lambda >0$