Show that for a light ray incident at an angle i on getting reflected the angle of deviation is `delta=pi-2i` or `pi +2i`.

Explanation

Form figure (b) it is clear that light ray bends either by `delta_(1)` anticlockwise or by `delta_(2) (= 2pi - delta_(1))` clockwise.
From figure `(a) delta_(1) = pi - 2i`
`delta_(2) = pi + 2i`