Q: For a hyperbola, the foci are at (±4 , 0) and vertices at (±2 , 0). Its equation is
(A) $\frac{x^2}{4} – \frac{y^2}{12} = 1$
(B) $\frac{x^2}{12} – \frac{y^2}{4} = 1$
(C) $\frac{x^2}{16} – \frac{y^2}{4} = 1$
(D) $\frac{x^2}{4} – \frac{y^2}{16} = 1$
Sol. ae = 4, a = 2
⇒ e = 2
But b2 = a2(e2 – 1)
⇒ b2 = 12
Hyperbola is $\frac{x^2}{4} – \frac{y^2}{12} = 1$
Hence (A) is the correct answer.