在空间直角坐标系下二次曲面
是（）.(填写曲面名称)；
A: 球面
B: 抛物柱面
C: 椭球面
D: 圆柱面
是（）.(填写曲面名称)；A: 球面
B: 抛物柱面
C: 椭球面
D: 圆柱面
举一反三
- 在空间直角坐标系下二次曲面[img=288x94]17d6095d6eb343c.png[/img]是（）.(填写曲面名称)； A: 球面 B: 抛物柱面 C: 椭球面 D: 圆柱面
- 在空间坐标系中,下列方程表示什么曲面? A: 圆柱面 B: 抛物柱面 C: 椭圆柱面 D: 球面
- 直角坐标下，无内热源、常物性一维非稳态导热问题的导热微分方程是() A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/f2c93fdbb58c4eea9f29ddc8f37e0943.png"/> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/2e37d9ca170d419582a5d6dbab09b76e.png"/> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/ef11632d8c6a490ab5fa94c51647b92b.png"/> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/96d7f423d7f04ee785ac2d03e6ff9b93.png"/>
- 若产生主动土压力为Ea，被动上压力为Ep，所需的档土墙位移量分别为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/1e8f0b9e0cb8465593753c5f11598176.png" >、<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/9088e679a4184965804bc72eeb0a0d41.png" >，则下述()是正确的。 A: Ea＜Ep，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/7a1afdb198494646a3e13d5a5fc63803.png" >＞<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/9088e679a4184965804bc72eeb0a0d41.png" > B: Ea＞Ep，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/7a1afdb198494646a3e13d5a5fc63803.png" >＜<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/1e329449603e4588bd4943ce452bde27.png" > C: Ea＞Ep，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/1e8f0b9e0cb8465593753c5f11598176.png" >＞<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/9088e679a4184965804bc72eeb0a0d41.png" > D: Ea＜Ep，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/7a1afdb198494646a3e13d5a5fc63803.png" >＜<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/9088e679a4184965804bc72eeb0a0d41.png" >
- 下列微分方程中为常微分方程的是（） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/cbf228ed319846a786045d6f0d92c025.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/14d9810e378e4a9aa35b205b9bd1bfad.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/a9b59e4bfb9e4db6893102d624b7c7c1.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202004/8f273eb6feb642e2850f4654eae6b238.png" >