Tangent of Rose Curve of Three Pedals

r = cos3t

References

• 2d Curves : http://www.2dcurves.com/roulette/rouletter.html

• Math World :  http://mathworld.wolfram.com/Rose.html

• Jen-Chung Chuan : http://steiner.math.nthu.edu.tw/ne01/tjy/dynamic/contants/FamousCurves-e.html

• Famous Curves Index : http://www-groups.dcs.st-and.ac.uk/~history/Curves/Rhodonea.html