设f(x,y)=﹛(x+y)sin1/x+y,x+y≠0 0,x+y=0,则在原点(0,0)处f(x 设f(x,y)=﹛(x+y)sin1/x+y,x+y≠0 0,x+y=0,则在原点(0,0)处f(x,y)()A. 不连续B. 偏导数不存在C. 连续但不可微D 分类:石家庄铁道大学隧道工程 题型:选择题 查看答案
()Paper cutting can only be used in China during t ()Paper cutting can only be used in China during the Spring Festival.AA. RightBB 分类:石家庄铁道大学隧道工程 题型:选择题 查看答案
3.The computer system _____suddenly while he was s 3.The computer system _____suddenly while he was searching for information on th 分类:石家庄铁道大学隧道工程 题型:选择题 查看答案