Question

If C is the centre of the ellipse 9x² + 16y² = 144 and S is one focus. The ratio of CS to semi-major axis, is-

• A. $\sqrt{7}$ : 16
• B. $\sqrt{7}$ : 4
• C. $\sqrt{5}$ : $\sqrt{7}$
• D. None of these

Answer 1

Answer: (D)

None of these

Answer 2

Since, x²/16 + y²/9=1 We have a² = 16, b² = 9

Now,e=$\sqrt{1–b^{2}/a^{2}}$=$\sqrt{7}/4$\Cs=$\sqrt{7}$

Co-ordinate of s are ($\sqrt{7}$,0)Hence,CS:

(major axis)=$\sqrt{7}$:2a\CS:(major axis)=$\sqrt{7}$:8.