Question

A variable point (x, y) satisfies the equation $\sqrt{(x - 1)^{2} + y^{2}} + \sqrt{(x + 1)^{2} + y^{2}}$ = 8, then eccentricity of the conic is

• A. ½
• B. ¼
• C. 1/8
• D. 1/$\sqrt{2}$

Answer 1

Answer: (B)

¼

Answer 2

The given equation is in the form of SP+S¹P = 2a where 2a = 8 ⇒ a = 4 and S(1, 0), S’(-1, 0)

SS¹ = 2 =2ae ⇒ e = ¼.