【简答题】E-R图中包括哪些基本要素?在E-R图具体用什么图形表示?
【简答题】(i)一阶线性非齐次微分方程 (2.28)的任意两解之差必为相应的线性齐次微分方程 (2.3)之解; (ii)若 y=y (x) 是(2.3)的非零解,而 是(2.28)的解, 方程(2.28)的通解可表示为 ,其中 c 为 数 任意常数; (iii)方程(2.3)的任一解的常数倍或者任意两解之和(或差)任为方程(2.3)的解。
【判断题】混凝土拌和物的均匀性对其硬化后性能影响很大,搅拌和振捣时间越长越均匀。
【单选题】绝缘锚段关节及关节式电分相承力索、接触线两绝缘子串上下应对齐,允许偏差________mm
【简答题】Dear Mr Fan, Yesterday I came across an interesting new book, which Iwould like to recommend here. It is an adventure story The title is Voyage to an Amazing kingdom. The publisher said that the novel...
【单选题】函数yx=A2x+8是下面某一差分方程的通解,这个方程是[ ].
【单选题】肾病综合征病人易自发形成血栓的主要原因是
【单选题】听力原文:Have you heard about an old book of the 19th century which sold for 300 thousand Euros last week? (A) I usually buy paperbacks rather than hardback ones. (B) It is really a best-selling one. (C) ...