【简答题】已知信号h(t)=ε(t一1)一ε(t一2),f(t)=ε(t一2)一ε(t一4),则卷积h(t)*f(t)=_____________。
【单选题】下列对不锈钢和铝合金车体的说法不正确的是?
【多选题】下面关于塑料的描述,()是正确的。
A.
用塑料制造汽车零部件,可大幅减轻汽车的质量,降低油耗
B.
在腐蚀介质中工作的零件可采用塑料制作,或采用在表面喷塑的方法提高其耐蚀能力
【简答题】f(t)[ε(t-1)-ε(t-2)]表示从信号f(t)中_____t=1到2的一段信号
【简答题】画出下列各信号的波形[式中r(t)=tε(t)为斜升函数]。 (1)f(t)=(2—3e-t)ε(t) (3)f(t)=sin(πt)ε(t) (4)f(t)=ε(sint) (5)f(t)=r(sint) (7)f(k)=2kε(k) (9)[*]
【简答题】Write something about your impressive character in around 60 words. The following structure is for your reference. My most impressive character is ... He/She is so ... that ... He/She is ... because w...