周期信号f(t)如下图所示，其直流分量为http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/bb02e5afe3fa474093913374442813ab.png
举一反三
- 已知信号f(t)的波形如下图所示，则f(6-2t)的波形图为http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/414e4bc7b0b44f6e8f660e9dd1189014.bmp
- 信号f1(t)和f2(t)如下图所示，f(t)=f1(t)*f2(t)，则f(-1)等于http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/0749958f4da44655959aea343dbe4d9c.bmp
- 下图所示序列f(k)闭合表示式为http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/e3088842d7014311aa5241014415b8f3.bmp
- 周期性方波信号如下图所示,则下列叙述正确的是http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/f6e3744eb62c46678fbb8c123d71d22f.png
- 图示结构C截面弯矩为<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/4f75b4fba9ff4be1b04a5e100c86c65e.png" /> A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/145877d7a442497f9fe1266fa394ba2e.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/1b6f8295e7bc44b0b8a2bee20e062fc4.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/18776e34a7504dfcbe40fbdf73958b14.png" /> D: 0