The angle between the hyperbola xy = c^2 and x^2 – y^2 = a^2 is

Ans: (A) & (B)

Sol: Differentiating xy = c² with respect to x, we get

$\large \frac{dy}{dx} = -\frac{y}{x}$

Differentiating x² – y² = a² with respect to x, we get

$\large \frac{dy}{dx} = \frac{x}{y}$

Clearly the two curves always intersect orthogonally.

Hence (A) and (B) are the correct answers.