(d) Given equation can be rewritten as $\frac{y^{2}}{k^{2}} - \frac{x^{2}}{( - k)} = 1( - k > 0)$ $e^{2} = 1 + \frac{( - k)}{k^{2}} = 1 - \frac{k}{k^{2}}$ $\Rightarrow \ \ e = \sqrt{1 - \frac{1}{k}}$
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.