2-15 已知 _(1)(t)=u(t+1)-u(t-1) _(2)(t)=8(t+5)+8(t-5) _(3)(t)=-|||-(t+dfrac (1)(2))+s(t-dfrac (1)(2)) ,画出下列各卷积波形。-|||-(1) _(1)(t)=(f)_(1)(t)*(f)_(2)(t)-|||-(2) _(2)(t)=(f)_(1)(t)*(f)_(2)(t)*(f)_(2)(t)-|||-(3) _(3)(t)= [ {f)_(1)(t)+(f)_(2)(t))[ |x(t+5)-a(t-5)] } +(f)_(2)(t)-|||-(4) _(4)(t)=(f)_(1)(t)({f)_(3)}^2(t)

[单选题]已知T（1）=9，T（2）=8，T（0）=5，Total=T（1）+T（2）+T（0），则Total=（）。A . 9B . 22C . 8D . 5

[试题]已知T(1)=9，T(2)=8，T(0)=5，Total=T(1)+T(2)+T(0)，则Total=()。A．9B．22C．8D．5

1-12 绘出下列各时间函数的波形图,注意它们的区别。-|||-(1) [ u(t)-u(t-1)] -|||-(2) cdot u(t-1)-|||-(3)

1-12 绘出下列各时间函数的波形图,注意它们的区别。-|||-(1) [ u(t)-u(t-1)] -|||-(2) cdot u(t-1)-|||-(3)

2-13 求下列各函数f1 (t)与f2(t )的卷积 _(1)(t)*(f)_(2)(t)-|||-(1) _(1)(t)=u(t), _(2)(t)=(e)

4.18 求下列信号的傅里叶变换。-|||-(1) (t)=(e)^-tg(t-2)-|||-(2) (t)=(e)^-3(t-1)g(t-1)-|||-(3)

求曲线=(t)_(2), =2t, =dfrac (1)(2)(t)^2在对应于=(t)_(2), =2t, =dfrac (1)(2)(t)^2点的切线方程和

与向量(1,2,3)^T,(3,4,5)^T都正交的向量是（）(1,2,3)^T,(3,4,5)^T(1,2,3)^T,(3,4,5)^T(1,2,3)^T,(

已知向量组α1=(1，2，-1，1)T，α2=(2，0，t，0)T，α3=(0，-4，5，-2)T的秩为2，则t=（）A. 1B. 2C. 3D. 4

[单选题]信号u（t）=10·1（t）-10·1（t-1）V，其中，1（t）表示单位跃函数，则u（t）应为（　　）。A.B.C.D.