User:Рајко Велимировић

elliptic integral

$C=2\pi ({\frac {\sum _{i=1}^{n}{\sqrt {a^{2}sin_{\alpha }^{2}\,\!i+b^{2}cos_{\alpha }^{2}\,\!i}}}{n}})$

$\alpha \,\!i=({\frac {2i-1}{n}}).45$

sin,cos-in degrees for a = b we get the circumference of a circle