【单选题】Which of the following statements about the matrix experiment is true?
A.
The subjects have to be highly intelligent to solve the matrices.
B.
A research assistant helps to count the correct answers.
C.
The subjects are paid according to how fast they solve the matrices.
D.
The researcher designed a variety of conditions for the matrix test.
【多选题】Which of the following equations are true for square matrices A and B?
A.
det(A+B)=det(A)+det(B)
【多选题】Let A be a singular nxn matrix, which of the following statements are true?
C.
Ax=b has infinitely many solution.
D.
for every nxn matrix B, AB is singular.
E.
A can be written by product of some element matrices.
【单选题】对裸露金属表面处理的程序是:去蜡除油( )、涂抹金属转换剂。
【单选题】51响应中断时,下面哪一个条件不是必须的
【单选题】We usually fold a letter in thirds , and is more common.
【单选题】Which type of pocket square fold is less suited for formal attire?
【简答题】A.hole B.none C.old D.fold