Reflection — Chapter Summary

X'OX and YOY are two mutually

X'OX and YOY are two mutually perpendicular lines that divide the cartesian plane into four quadrants. X-axis and Y-axis taken together are called co-

For a point P

For a point P, OA is the X-coordinate, called the abscissa, and AP is the Y-coordinate, called the ordinate. A point has coordinates (x,y). A point on

When an object is seen

When an object is seen in a mirror, its image is obtained on the other side of the mirror, called its reflection. The mirror line is called the axis o

A point is an invariant point

A point is an invariant point with respect to a given line if and only if it lies on that line. Such a point does not change after reflection.

For a point P(x

For a point P(x,y), reflection in the X-axis gives P' = (x,-y). Only the sign of the ordinate changes. The formula is Mx(x,y) = (x,-y).