Given that y = e^–x …(1) and y = e^x ….(2)

Substituting the value of y in (1),

e^–x = e^x

⇒ x = 0

And y = 1 (from 2)

On differentiating (1) w.r.t. x, we get

On differentiating (2) w.r.t. x, we get

∵ m₁× m₂ = -1

Since the multiplication of both the slopes is -1 so the slopes are perpendicular to each other.

∴ Required angle = 90°