Question

If e is the eccentricity of the hyperbola x²/a² - y²/b² = 1 and 2θ is angle between the asymptotes then cosθ = 

(a) 1/e

(b) 1 - e/e

(c)  1 + e/e

(d) None of these 

Answer 1

Correct option  (a)  1/e

Explanation:

we know 2θ =2tan^-1(b/a)

tanθ = b/a

e = √1 + tanθ² = secθ

cosθ = 1/e