【简答题】已知|z 1 |=|z 2 |=|z 1 -z 2 |=1,则|z 1 +z 2 |等于______.
【简答题】SectionD Directions: In this section, you are going to read a passage with ten statements attached to it. You may choose a paragraph more than once. Each paragraph is marked with a letter. a nswer th...
【简答题】已知两个系统有这样的关系 , r 1 (t)=Cλ(t)和 r 2 (t)=B T γ(t) 证明:如果系统起始是静止的,则这两个系统的输出冲激响应有下列关系 h 1 (t)=h 2 (-t)
【判断题】两梁的跨度、承受载荷及支承相同,但材料和横截面面积不同,因而两梁的剪力图和弯矩图不一定相同。
【单选题】已知z 1 ,z 2 都是虚数,则 z 1 = . z 2 的一个必要不充分条件是( )
【判断题】4012801 若两梁的跨度、承受载荷及支承相同,但材料和横截面面积不同,则两梁的剪力图和弯矩图不一定相同。
【单选题】已知系统的输入x(n)与输出y(n)之间的关系为y(n)=x(n)x(n-2),则以下关于该系统特性的描述,不正确的是
【单选题】已知一个LTI系统,当输入 时,输出为 。根据该输入输出关系,判断下面哪个理想低通滤波器系统,有可能是这个LTI系统?
A.
截止频率为5π , 幅度为2/5,τ=1/5 ;
B.
截止频率为π , 幅度为1/5,τ=1/5 ;
C.
截止频率为4π , 幅度为2/5,τ=2π/5 ;
D.
截止频率为3π , 幅度为1/5,τ=1/5 ;
【简答题】Section D Directions: In this section, you are going to read a passage with ten statements attached to it. You may choose a paragraph more than once. Each paragraph is marked with a letter. a nswer t...
【简答题】SectionD Directions: In this section, you are going to read a passage with ten statements attached to it. You may choose a paragraph more than once. Each paragraph is marked with a letter. A nswer th...