Rays at a convex mirror

A convex mirror has the same four special rays as a concave one, but its focus and centre of curvature lie behind the mirror, so the rules talk about rays heading towards them.

(a) Along the principal axis

A ray along the axis comes straight back along it.

(b) Parallel to the axis

A ray parallel to the axis reflects outwards, as if it came from the focus behind the mirror.

(c) Heading towards the focus

A ray heading towards the focus is reflected parallel to the axis.

(d) Heading towards the centre of curvature

A ray heading towards the centre of curvature comes straight back along its path, because any line from C meets the mirror at right angles.