记得是这样的。http://twebmail.mail.126.com/js4/read/readdata.jsp?sid=NAnpWDzcXDXllzjUbfcczQBhUnwFagYS&mid=37:1tbiJQ-kDk517mBpeQAAsl&part=2&mode=inline&l=read&action=open_attach
二阶导数不会求,一阶就会,呵呵,帮不到你呀