已知系统开环传递函数
，开环零点有三个。（ ）
，开环零点有三个。（ ）
举一反三
- 下列结论正确的是( ) A: 如果函数f(x)在点x=<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/fdcb3c002c53441fa69fd9fc3076a5be.png" />处不可导，则f(x)在点x=<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/fccedfd766654505ba6969e49597bb90.png" />处也可能连续 B: 如果函数f(x)在点x=<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/450601f103e541c59a2bcaf43473c913.png" />处可导，则f(x)在点x=<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/ac603e6c25944a939bc20a352e35e40b.png" />处连续 C: 如果函数f(x)在点x=<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/59143c94d1554ce7b1c4188c63dd7dc8.png" />处连续，则f(x)在点x=<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/10cd24ef2c2b47b08193284458b6c8cd.png" />处可导 D: 如果函数f(x)在点x=<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/e1b59bf3878c483f817cd90a0b46acea.png" />处不连续，则f(x)在点x=<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/a1d323d5a3e14eff887de62c708c931f.png" />处不可导
- 下列函数表达中，（ ）是周期信号（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/fa28c4df306a4768855eadcf32f77987.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/7a1a43bddcbc4b438f49428cef75ea64.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/5b67d7d31dd34862904bc3d9086668ed.jpg" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/377afdab17404edf84b525cd9e974df1.png" />
- 在力法方程的系数和自由项中（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/3a7ac606e16647f4b6a3d2d11beb76bc.png" />恒大于零 B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/11f1ba644a064f5fb28da6ae46cc0df2.png" />恒大于零 C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/a6b6c6466e6646bf8d42d75ebc28748f.png" /><img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/9e771c22268e4410a0f86c6d4ba84df5.png" />恒大于零 D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/4e79f0d189ab4ff69dd07e05ffbf4efc.png" />恒大于零
- 下列关系正确的有（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/0c9a6360c85f4ff9bdb2b17b576df2e0.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/09c3ca64214040d89eaa8534fa21d895.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/3d88f37ec20c4604a8387c0e1088ad34.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/d48f61b369aa425384b1d565afb5d073.png" />
- <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/c113ee40aaf64a38b94a3fe9473fefa3.png" />图示刚架，为使横梁水平位移为零，已知各杆EI=常数。试确定集中荷载的大小（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/c3b779d267b14c18b4aeace388f76b3b.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/930068af04244911921a8820bbf2b7e6.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/c77e421cb5a44f019bb9f461066be1e6.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/8d32e910b61b4a91a7ed3692a3e83b6e.png" />