【简答题】设函数f(x)与g(x)在区I司[a,+∞)上连续,按照下列给出的条仵,判断广义积分∫ a +∞ [f(x)+g(x)]dx是否收敛,并说明原因: (1)∫ a +∞ f(x)dx与∫ a +∞ g(x)dx都收敛; (2)∫ a +∞ f(x)dx收敛,∫ a +∞ g(x)dx发散; (3)∫ a +∞ f(x)dx与∫ a +∞ g(x)dx都发散.
【简答题】若有以下定义和语句: struct stu { int num; int age; }; struct stu[3]={{1001,20},{1002,19},{1003,21},};则表达式的值为1002的是( ).A. stu[0].num B. stu[0].age C. stu[1].num D. stu[1].age