Trace and Locus

Objects can leave a trace in the Graphics View when they are moved. Use the Context Menu to switch this trace_on Trace On. Then, modify the construction so that the object whose trace you turned on changes its position and leaves a trace.

 

Note: You can turn off the trace of an object by un-checking Trace On in the Context Menu. The menu item view-refresh Refresh Views in the View menu clears all traces.

 

You can also let GeoGebra automatically create the locus of a point by either using tool
mode_locus_32.gif Locus with the mouse, or enter the command Locus into the Input field.

Note: The point whose locus you would like to create must depend on another point’s movement, which is restricted to move along an object (e. g., line, segment, circle).

 

Example:

·        Create a segment a between the points A = (-1, -1) and B = (1, -1).

·        Place a point C on the segment, so it is restricted to move along segment a.

·        Create a point P that depends on point C (e. g., P = (x(C), x(C)^2)).

·        Use either tool or command Locus in order to create the locus of point P in dependence on point C:

o   Tool mode_locus_32.gif Locus: Click first on point P and then on point C.

o   Command Locus: Enter Locus[P, C] into the Input Bar and hit the Enter-key.

·        Note: The locus created in this example is the graph of a parabola on the interval
[-1, 1].



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