Cotangent

A reflection is a "flip" of an object over a line. Let's look at two very common reflections: a horizontal reflection and a vertical reflection.

Horizontal Reflection (flips across)

How to draw the reflection of a plane figure

Label the vertices of the original figure as A, B, C,.... Draw a perpendicular line from the mirror line to each of the vertices. (The distance line should be at a right angle to the mirror line).

Extend the line from the vertices to the opposite side of the mirror line by the same distance. Mark the position of the new vertices.

Draw lines to join the new vertices. Label the points of the reflected image as A', B', C',...

Examples of transformation geometry in the coordinate plane...

Reflection over y-axis: (x, y) (-x, y)

Reflection over x-axis: (x, y) (x, -y)

Reflection over line y = x: (x, y) (y, x)

Solution: