【判断题】需要系数是供电线路的计算负荷在所有设备功率总和中所占的比例,也可理解为建筑内所有电气设备同时工作的概率。
【单选题】实二次型 为正定的充分必要条件是______.
【单选题】二次型【图片】正定的充分必要条件是( ).
【单选题】It can be inferred that the writer thinks that engineering curricula are
A.
strengthened when they include courses in design.
B.
weakened by the courses designed to develop mathematical skills.
C.
weak because they include some nonscientific components.
D.
strong despite the absence of nonscientific modes of thinking.
【简答题】Nina thinks that when
you live with a host family, you learn ___ .A. their language B. about their country
【简答题】n元实二次型XAX是半正定的充分必要条件为它的标准形中n个系数全非负.