Tangent of  Bullet Nose

 x = a cos t

y = b cot t

References

• J. Dennis Lawrence. A catalog of special plane curves, pp. 128-129.

• 2d Curves : http://www.2dcurves.com/quartic/quarticb.html

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

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