MCQ
A hyperbola, centred at the origin, has transverse axis 2 a . If it passes through a given point $\left(x_1, y_1\right)$, then its eccentricity is
- A$\sqrt{\frac{x_1^2-y_1^2- a ^2}{x_1^2-y_1^2}}$
- ✓$\sqrt{\frac{ a ^2-x_1^2-y_1^2}{ a ^2-x_1^2}}$
- C$\sqrt{\frac{ a ^2+x_1^2+y_1^2}{ a ^2-x_1^2}}$
- DNone of these