To describe a reflection we need to specify the mirror line. To do that we give the equation of the line. Remember that the mirror line is a perpendicular bisector of the line segment from the object to the image.
Click the "On/Off" button on the applet to start it.
As usual you can move the mirror line by first clicking on the mode button. Try to find patterns that tell you where the image is if you know where the object is. For instance if the mirror line is the line y=0, then the image of a point (x,y) is the point (-x,y). Some interesting mirror lines to investigate are vertical lines, horizontal lines, and lines of slope 1 or -1. Pay special attention to the image of a point when the mirror line is the line y=x because you will meet it again when you study inverse functions.
e-mail: C. Mawata