• 2021-04-14
    下图所示序列f(k)闭合表示式为http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/e3088842d7014311aa5241014415b8f3.bmp
  • f(k)=ε(k-3)-ε(k-7)
    本题目来自[网课答案]本页地址:https://www.wkda.cn/ask/xattzjxjtmxayxo.html

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    内容

    • 0

      下列微分方程中常微分方程的是( ) A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/c24b125c0b534b7696bf33f1e7b98c4c.png"> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/2c9f694c97e9426596d13bed4bd474da.png"> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/7ee1366ebe7a40aa868a143ba15c6ed0.png"> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/d46e4fa33ea0443a938c267c2f07c6b4.png">

    • 1

      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

    • 2

      在下图中,螺纹连接画法正确的是( )。 A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/388e6231e1fb4ef09858a435d5076944.jpg" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/5c2ff529f94044ffaf8ccbc591499df6.jpg" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/578fcb9927c044a4b982bf3e7e7616a3.jpg" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/bb9122c2834242f4afba03761d066fb8.jpg" />

    • 3

      下列各表达式中错误的是__ A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/dd20f9d2c1984b1f95ffd89fdf3fed61.png"> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/a7138f62245042a4a604eee2ce27ae93.png"> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/53b05040965a40629cf24d6c90bc7e27.png"> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/8bbfc40de0d6420aa10e572ce4a7b5dd.png">

    • 4

      下列配合物属于螯合物的是( ) A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/8f51868d3100497c9f78fe09ba550e3f.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/025b639d0fe9456997a0191bdeb0019a.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/154fd181ff4d421d96ab4d50e3052020.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/fbd3f97989994e40a247c9ea17663bd0.png" />