ChaseDream

标题: JJ13 [打印本页]

作者: heninzhang    时间: 2011-12-29 15:05
标题: JJ13
我怎么算出来是4R^2(2+根号2)




欢迎光临 ChaseDream (https://forum.chasedream.com/) Powered by Discuz! X3.3