下列结论中正确的是 ( )
A: 若数列收敛, 发散, 则和均发散
B: 若数列与收敛, 则和均收敛
C: 若数列与发散, 则和均发散
D: 若, 则必有或
A: 若数列收敛, 发散, 则和均发散
B: 若数列与收敛, 则和均收敛
C: 若数列与发散, 则和均发散
D: 若, 则必有或
举一反三
- 变化的磁场激发的感应电场满足 ( ) A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/f636147417d144a4ba1c35b5c019b5bd.png" />,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/c85cf7ff1a2b4ac1a1690f3c06424b52.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/d249e3e9419547bb942b3e012cb266ac.png" />,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/a53d71dd9ba14f6889f4a46ecb00b923.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/466f114b82234936ab3612322e18ae5b.png" />,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/a5968023d69c492a9d3559f5a59d81ba.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/836158ae6c8944a780cf31e1deb309a0.png" />,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/9b1930e33b5e4af78f37e7d0ca350c2d.png" />
- 在能够引入磁标势的区域内 ( ) A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/03686a49cd944df9ba1b005d65f92230.png" />,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/df6b1c014a5045c1b6d26dd1b62ee428.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/6f3c4fe9e6df47239d7229e10c812aae.png" />,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/df6b1c014a5045c1b6d26dd1b62ee428.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/03686a49cd944df9ba1b005d65f92230.png" />,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/2f286a1497e94fc9ae658101f2ad49f7.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/23ebdfdb3444448e9a6f3c1342ce4b92.png" />,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/2f286a1497e94fc9ae658101f2ad49f7.png" />
- 空心圆轴的外径为D,内径为d,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/c268745e2545426ca7e4f20847abad16.png" />=d /D。其抗扭截面系数为( )。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/c8afd0b0bde9471e9174ef404bfa0bd3.png" /> ; B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/0d280ef40b30438aacd3ab8ee129a3d2.png" /> ; C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/263e7ba4c4c24cdd853583eb10f4e0cb.png" /> ; D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/54112e744a1e487fa709a47f5a78160d.png" /> 。
- 进行轴心受压杆的设计时,合理的截面形式是根据 原则确定的。( ) A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/351866917b1d4286b2f3c9fec7fb4b67.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/bee3290fbc9f4da78075a187033cef2c.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/08d9d0f06d4f4b2396e343d5052d59f4.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/07a2642ce15b4516b2290e87fb1a371d.png" />
- 压弯构件临界状态时,截面上的应力分布可能有三种情况,不可能出现的情况为(图中“+”表示拉应力,“—”表示压应力)( ) A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/3488e21be56c455b8ab3263070b4ea2a.PNG" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/f94fd3e7151945f7855de94519f45701.PNG" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/76e3865bfbdf440b82dcd3ef1c7bf851.PNG" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202110/2b9fe89b8e3a4c9c928bc7abbcdf91f4.PNG" />