数学图形(1.39)TN constant curve

这是个类似巴黎铁塔的曲线.

#http://www.mathcurve.com/courbes2d/tn/tn.shtml

vertices = 1000

t = from 0 to (PI*0.999)

a = 10



s = sin(t)

c = cos(t)



y = -a*(c*c + ln(s))

x = a*s*c



y = limit(y,  -100, 100)

面的形式:

vertices = D1:360 D2:100

u = from (0.01*PI) to (PI*0.99) D1

v = from 0 to 20 D2



s = sin(u)

c = cos(u)



y = -v*(c*c + ln(s))

x = v*s*c