coshy 数学中表达什么

是双曲函数中的双曲余弦chx=[e^x+e^(-x)]/2

另外还有些双曲函数:
双曲正弦:shx=[e^x-e^(-x)]/2
双曲正切:thx=shx/chx=[e^x-e^(-x)]/[e^x+e^(-x)]
双曲余切:cthx=chx/shx=[e^x+e^(-x)]/[e^x-e^(-x)]
双曲正割:sechx=1/chx=2/[e^x+e^(-x)]
双曲余割:cschx=1/shx=2/[e^x-e^(-x)]

did u mean cosine?
it's a kind of cosplay of sine~

应该指双曲函数的一种吧
http://baike.baidu.com/view/478416.html?wtp=tt