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GeoGebraGeoGebra Classroom

Polar coordinate system, Archimedean spiral

The polar coordinate system is a two-dimensional coordinate system in which each point on a plane is determined by a distance from a reference point and an angle from a reference direction. Converting between Polar and Cartesian coordinates: Task: The curve is given by polar equation r = 2+2cos φ. Determine the point with minimal curvature. First, rewrite polar coordinates to the cartesian coordinates. Instead of the greek letter φ, we can use the letter t. x = (2+2cos t).cos t y = (2+2cos t).sin t

Determine the point with minimal curvature (= krivost) on cardioid.

Archimedean spiral

Start the animation of revolving parameter a (left down corner). Value of slider u specify the position of osculating circle (red).
Stop the animation and set up the trace on for osculating circle. Then change the value of parameter u on red slider.