the article on polar coordinates is my main reason for joining. I am interested to know if any Chinese mathematicians have contributed to the origin of polar coordinates?
I am thinking particularly of Lai Zhide and his contribution to the Yin Yang Taijitsu. I have a reference to the Chinese astrologer/astronomer/magi creating the Taijitsu by astronomical observations using an 8 foot shadow pole and mapping this out on a 24 segment 6 ringed concentric circle. http://www.chinesefortunecalendar.com/yinyang.htm.
The I Ching was then adapted to this Yi to give further insights and relationships by Lai Zhide (16th century).
Although there is no mention of polar coordinates per se , i do not know enough Chinese to pick out the astronomical references in the I Ching. These will of course be philosophical in meaning but these will also be actual astronomical references,giving directions.
The relation to the Yin Yang gives a kind of compas refference, that is clearly polar.