下列选项哪些是立体干燥花（ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/e0a75b2333b848a4b2deab3fd3cadfaa.png"> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/d11fc544a6f94867affb44c7c8facf5a.png"> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/66be30e1dc6b4777b36729ae181aefeb.png"> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/0b0d4724e987493fb7eb224f50bf0ddf.png">

森林救火模型中，队员人说x，损失费用<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/a7b3bb68726943bf850131151512da56.png" >表示，救援费用<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/10d199675f734d4492fbe27b528023f7.png" >表示，目标函数是:（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/af6eaeb0e41646759e07de5609baf6e2.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/eb052c5d448843d180f7e28d97ea2767.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/b5868eec78f94cf5a428f254e6195d8b.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/0203e76fa2424495a2072562b8173c3d.png" >

某人举步上楼梯，每步跨1个台阶或2个台阶，设上n个台阶的不同方式数为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/62999550ec1547439283cd9872427fdc.png" />，则( ). A: 初始条件为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/e5083263b09044c1b6e95baed3ef628c.png" />=1，<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/07aa95ceccda433f8e9432a186fae005.png" />= 2, 递归关系为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/ad0a958e510040be8f4253d0526d7ce5.png" />(n≥3). B: 初始条件为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/d5cc33a9d0714d3fbba386ccff5f8aaa.png" />=1，<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/34a42e4a62ea448db919ffa607f5de44.png" />= 1, 递归关系为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/c3dc9b741afa4ae68983bc1d5db5e065.png" />(n≥3). C: 初始条件为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/405917811f9845e1915af00c9fa30c79.png" />=1，<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/ccd3e7a79651413b8cd22dbf5cd05ac8.png" />=1, 递归关系为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/0acc9967cdab4f31a918b5fc8fe38608.png" />(n≥3). D: 初始条件为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/245baeee86b943e4bd7f1c39803b142c.png" />=1，<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/a06359868bb1457e81ab7e102d212630.png" />= 2, 递归关系为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/0aee376a7bfa44da9f431ecb21e6c787.png" />(n≥3).

长方体一个顶点的三个侧面的面积分别是 <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/177f124c9d4844ee9cb80dbdfd1e53b2.png" />，则长方体的体积为（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/cca69e5a182840899ed8c0ef411d6c15.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/598019215ddd499f952f644dc14ddb0b.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/f293e69522584f56b51e00d7c7210bec.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/9364d6fbc3864b29b430b272126f8119.png" />

下列时间复杂度最好的是（）。 A: O<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/fa34894ec21a44e399feadbac71a8340.png" > B: O<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/525b0bb57bcb42cf9e998f6c6a933991.png" > C: O<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/80351fa4ddde48a997031c49dc07fa7f.png" > D: O<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/28bd9a50afb741ff8a4805c6d22066f0.png" >

用于计算生活垃圾产生量的公式是（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/730728c6b86c45b48207637d9ddf3d55.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/a12b43de83f546fbb215621eef41e521.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/796bb7cad2e840a794ba56d31772ba6e.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/e5a15dd29d974749a8e7dd3b38415d18.png" />

非线性系统状态空间表达式的矢量矩阵形式为（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/18f8e73a712b40dfb70c1e2631d84c95.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/4bb2d001d15c40a8a300932d7ace7fee.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/8ec872bfb564441fb15ffd9d0478bd26.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/f4126bd26c18419b99c27f1a37ce32eb.png" />

设个体域D是正整数集<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/bb49a9cddeaa40059632876d46e1298b.png" />，则下列公式中真值为真的公式是( ). A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/4db4b88de97b4847a6f2b4090e1371fb.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/c1f2498d60dc44da87a3b72af11eaba6.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/9e2d538cbefc45d5afe417f98245df4d.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202010/1cdf577968f74f709f161cd354e74195.png" />

有4个顶点，如何连接4个顶点所用的管道最短？( )。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/14e274d424f2476989fefc7ac0a1b877.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/b945aa40fe36479a91b263c96244260d.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/0323cba80b54453bbb587009da3dbdb7.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/5b0e221bf38e4e15b14c31f5232371d5.png" />

下列属于两逻辑变量A、B的最小项的是（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/a50ff59fb14040e8a6baffd97e5ab7c2.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/e83307bbe2b5455183bd9be5e980805a.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/65230f27a98b481e99a69e6c501470a1.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202010/9a9202db53d34cb1b69b0970c536eaf7.png" />