下面的表达式中，正确有？ A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/0e169fdf5e354dd4af80ea6386ddeca5.png"/> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/5124889b558b4186ba4140ca7692d717.png"/> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/f3d2d0d80b744f74899371cae0395a71.png"/> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/2af6ef9203e94ea2b993e1ad4d99e5d2.png"/>

历史曲线构件的图标是( )。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/dfb6b619f35547c590f6e6c6aab95b3f.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/e7e0aaa5f6e84ba89410cc93b06a451a.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/354425393230484ab64d64a718bd9bad.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/1f794e99ed004e3190fa5181c32fe4e8.png" />

下列哪个结果是小振动问题的广义动量？ A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/88a2b0c72d824141a289c01e09f1645f.png"/> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/0803ba58456c4a3290e9bdb99759147f.png"/> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/ab24cb59059348a3b0ba6cc4e5fca989.png"/> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/916cb85fc9d84dda90b43a5f671092a9.png"/>

下列哪个结果等于拉格朗日函数对时间的导数？ A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/71e251af38d1445ba51641b664c72b4e.png"/> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/dc04aa798b3d404cb6c1f5e3d08b3242.png"/> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/007e2f33b2c04914b2c60d6c01def954.png"/> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/81eedf26bc254250a56919c9fb55ff1e.png"/>

x(t)的频谱为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/5bcfe4175fcb4fabbdb5f40d00b5343e.png"/>，则<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/45b1670ebd6245ff99cc376a8048a645.png" />的频谱为（ ） A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/09bc7326832a4a1fba983e74c6d85d35.png"/> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/95fca346a74e4a6cbba601cd6d9e26bf.png"/> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/6bf6b83111ad45efac7eb9a37a245c68.png"/> D: 其余选项都不对

用作花钵的植物高度控制在（ ）比较理想? A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/23b52d3a814d4457b43fbcbfd03aa855.png"> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/93c6f6bddd444e5c932ec666b0eb7b08.png"> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/249c386b45104bcfa5480f33469fdc8c.png"> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/244d73f3b91047b1b5d67bd58af45514.png">

MCGS嵌入版组态软件历史表格的图标是( )。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/536f0628f8c34abe91a754f840ab6b48.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/711a0648935040e29e0ad51df9aab912.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/8eac11daec78403c8885400b32c65dc1.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/23d6fb88adca49ad9982ea9a4381efab.png" />

MCGS嵌入版组态软件，插入元件的图标为（ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/994aaad4457d4681a93b1b7510a1cc32.png"> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/8060157e508b4324b30674602b93d3ba.png"> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/3d7b0289666143de92115d57616ffc86.png"> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/c0ead39dc09740c1b3b682da3e3fa0d7.png">

MCGS嵌入版组态软件，保存元件的图标为 （ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/74ef980afc09440e9ee2705d1551a8ad.png"> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/54b48895c9694d499f75d06b316d0ecc.png"> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/3d3ad6a3d2854f04b8059a86c771beaa.png"> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201911/e4580e0c56a44b569f108fb751a98f09.png">

设随机变量X~N(4,2)，则其特征函数为(). A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201911/357ad388efa144a1a2b824e2b1ded239.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201911/d52e72841a81484981168cbb693bad24.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201911/00e1e0c2bba04889b58eb483c88821fb.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201911/1851c30670244a5c821128d6c44a3ecc.png" >