Abstract
MacLaurin was the first author to investigate pedal curves (1718).We have two subjects to discuss the pedal curves. These two subjects can be roughly distributed as follows:I. We introduce the tangents and osculating circles of the pedal curves equation. II. Construction: construct the tangents and osculating circles of the pedal curves.This paper presents the tangents and osculating circles of the pedal curves in Cabri Geometry II, an interactive dynamic software of geometry.