双纽线
所围成的区域面积可用定积分表示为（ ）
A:
. 
B:
C:
所围成的区域面积可用定积分表示为（ ）A:
. B:
C:
举一反三
- 在常体力的情况下，平面问题的应力函数与应力分量之间的关系正确的有（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/13db38e0be0f42a8aa8220026ad6d3e5.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/9178e461e0974317b42e0e9b59149047.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/d66f684595a1482283e180c311c9e8f4.png"> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/20a366b5fd844f65a1716a7a6078b968.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/f4a5a69f1a264e5b8f28fa968022cbb0.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/b77e7d17deb548619be88f5ed437af81.png"> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/cb0ce22cc89447b5b3a914b1a55209a0.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/d56afcca319e46a2be256f91ac5e289b.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/d6a4d2e83f9448cdbfec37887ffd53a9.png"> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/1f5fa1a13a4c48698715e2b1814291b4.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/06c0cb7f6e184b18a6b345acff91e4bb.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/c59f70ea241546dd948d2f09b5821ac6.png">
- 下面和声连接对的是（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/cfbbaacbd31140caada6de1a82879cf1.jpeg" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/cfbbaacbd31140caada6de1a82879cf1.jpeg" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/cfbbaacbd31140caada6de1a82879cf1.jpeg" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/cfbbaacbd31140caada6de1a82879cf1.jpeg" />
- 下列不属于弹性力学平面问题的是（ ）。 A: 应力分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/14e55ab2cde14d22a44bff9ea88507d2.png">，只有应力分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/c3c1da2ca4e64ad19e0fbc1764ed6bcc.png">存在，且它们都仅为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7bffc15d98b240c584d659d1aa155670.png">和<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/dbee1ba1e52447b2bb076c7d812d3e5c.png">的函数 B: 应变分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/ea8a2b953bca4b598b6781db39c5f5bf.png">，只有应变分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7877a5c9731d4b54b054875be6f3ea05.png">存在，且它们都仅为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7bffc15d98b240c584d659d1aa155670.png">和<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/dbee1ba1e52447b2bb076c7d812d3e5c.png">的函数 C: 位移分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/1e6aeef29fa74143bf306acfc598d7e4.png">，只有位移分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/0a59276fcf7e48d8bc4d1fb7313cc78d.png">存在，且它们都仅为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7bffc15d98b240c584d659d1aa155670.png">和<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/dbee1ba1e52447b2bb076c7d812d3e5c.png">的函数 D: 薄板弯曲问题
- 延时环节<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/5c7e2dbac7e649e9ba2da3656a964d45.png" />，其相频特性和幅频特性的变化规律是（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/0831ed5bb7a5495b9632eb9be36d703d.png" /> dB B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/a2358c63853d4f50a2cf9003407f588f.png" /> dB C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/23119fba416f46db820927d5fcd66a7d.png" /> dB D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/67d0e95b64db43bd9c955f6cf62e36a2.png" /> dB
- 坐标系{B}相对于坐标系{A}绕Z轴旋转<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/0e7f1303cace4a9fa888211d1b94e3c3.png" />度，坐标系{B}中的矢量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/06f5b17a51fb43deb2e94fe685b5b511.png" />在{A}中的坐标表示为（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/86783ba498314fdfa0c22abffc2891f2.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/ea644ea443b74b54b41c89eff9db781a.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/dddcfd36e178435c8a82f63cc982fd2b.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/1d5f3187c48f447eb117b0005e7ca646.png" />