一根直径为d=16mm、长为L=3m的圆截面杆，承受轴向拉力P=30kN，其伸长为ΔL=2.2mm，则杆材料的弹性模量E为（ ）。
A:
B:
C:
D:
A:
B:
C:
D:
举一反三
- 定积分<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/40a96e021d184b53859fdd4926e16b1b.png" />等于（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/cde1094a25c3497f80373bc771f80513.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/54c773851e0348059f1ce37a91a948fc.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/e27823bdfcdc467faf41d0b330b00e15.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/6503ac83a84d4ae2ac241d6c3e33a59a.png" />
- 逻辑函数<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/520c51d784294a05b7c0a58e9a006f8d.png" />的最小项之和表达式为（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/b29de4567e024993be29cf0772062626.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/c828662b80bf46969b13b8c2e141d796.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/e89e7dff660747259c21fedcc7586e09.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/11fe1998fad740bba3df120af96ae8a9.png" />
- 逻辑函数<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/7a28ab990f564e25a47249ee94eb1f20.png" />的最简“与－或”表达式为（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/13627d46b788407ea818c87bbc009fe0.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/5df5979516fe45758b8a1e4e729722a6.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/bab1ddffc2c24f4bbace96c67048e662.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/0b57d6e41e5242b2a1999a3beaf9b210.png" />
- 下列（ ）不属于中心支撑。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/b7b36299d8fb49c58fa83ef9ce64a739.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/73633e9d8616459490af2a472a7f9649.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/af19ae1f1e1f42ddbd45522c9ddbbea7.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/11cef2be0b5b46f6a30e71db95fd8476.png" />
- 一元线性回归模型<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/08f92b38e98040ae8fae5a00cc3d58cf.png" />的经典假设包括（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/ef3467d1ca854d138e84f66981b5667c.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/396f61967f2d4bbcabcdd46becdad8d8.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/b178f5b4d9e147a382f0da1ce41e36de.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202103/493466511c304cafad3b3e0543a2ba73.png" />