【单选题】设 为 阶矩阵, 在齐次线性方程组 中,如果 ,那么此方程组解的情况是( )。
【简答题】已知椭圆 C: x 2 a 2 + y 2 b 2 =1(a>b>0) 的右顶点A为抛物线y 2 =8x的焦点,上顶点为B,离心率为 3 2 (1)求椭圆C的方程; (2)过点 (0, 2 ) 且斜率为k的直线l与椭圆C相交于P,Q两点,若线段PQ的中点横坐标是 - 4 2 5 ,求直线l的方程.
【单选题】What is an "operating" cycle?
A.
A cycle of transactions that converts cash inflows to cash outflows, or vice versa.
B.
A cycle where there is receipt of funding from investors, those funds are used to generate returns from investments and operations, and then the funds are returned to investors.
C.
A cycle where a property is purchased that has long-term future benefits for the enterprise, which ultimately results in cash inflows, and then the property is disposed of.
D.
A cycle that involves the purchase of items such as inventory; production, sales, delivery of goods or provision of services; and receipts from customers.
【单选题】可编程并行接口芯片8255能够在一个口上同时具有8位输入/输出功能的是:()
【简答题】一片可编程芯片8255有【1】个8位的并行端口.
【简答题】What is an operating system? How many types are operating systems categorized into? What are they? What is the embedded operating system applied to ?
【简答题】What can be inferred from the last paragraph?( ) [A] Newspapers are now operating their own websites. [B] Websites begin to involve in the traditional newspaper business. [C] Competition on ads will b...