﻿功能:求雅克比椭圆余弦

格式: JacobianCn(u, k)

u  : 由{EllipticF<矩阵运算\EllipticF>}函数输出的值.
k  : 一个度量模数的参数


说明:
1. JacobianCn(u, k) = {Cos<矩阵运算\Cos>}({JacobianAmp<矩阵运算\JacobianAmp>}(u, k))

参考:{Jacobi椭圆函数<https://mathworld.wolfram.com/JacobiEllipticFunctions.html>}

例子:
u= [ 0.25000000000000    0.68000000000000 ]
c = JacobianCn(u, 0.1)//回车得到如下结果
c =
[ 0.96891878395585    0.77787294128833 ]