﻿功能:求反余弦值

格式:Acos(z)、Acos2(z)

说明:假如z为一个复数,那么
Acos(z)=-i*{Log<算式解析\log>}[z+(z^2-1)^0.5]
Acos2(z)=-i*{Log<算式解析\log>}[z-(z^2-1)^0.5]

根据反余弦的定义,{Cos<算式解析\cos>}(Acos(z))=z,{Cos<算式解析\cos>}(Acos2(z))=z

例子:
a=acos(4+5i)//回车
a = 0.901979751468969 - 2.5513216254757i

cos(a)//回车
ans = 4 + 5i

b=acos2(4+5i)//回车
b = -0.901979751468968 + 2.5513216254757i

cos(b)//回车
ans = 4.00000000000001 + 5i