若<img src="http://edu-image.nosdn.127.net/_PhotoUploadUtils_5e87b1af-bca5-443b-a243-291827849f02.png" />,则<img src="http://edu-image.nosdn.127.net/_PhotoUploadUtils_ad6fa5ac-dbcf-4b8b-8daa-181c5a784826.png" />的初值<img src="http://edu-image.nosdn.127.net/_PhotoUploadUtils_db6a652c-73b6-49f0-aa72-b78bfc327b03.png" />为? 0|不存在|1<br >|-1

<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/2205d9f03e724a04b34f2f1045309079.png" />的幅频响应是，幅频响应是。 A: 1，<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/760d7fcc2f264ed1b10fb836cb48f565.png" /> B: -1，<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/21f685d2962e4b6993bfcaa513bdbf68.png" /> C: 2，<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/57267e995f86426899ce3cc0177a2343.png" /> D: 1，<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201903/ea8ba62853a94a15a5620c5165e3594a.png" />

<img src="https://image.zhihuishu.com/zhs/teacherExam_h5/COMMONUEDITOR/202104/8fe7daa028204d39a2138b39d2f9d72d.PNG" /> A: <img src="https://image.zhihuishu.com/zhs/teacherExam_h5/COMMONUEDITOR/202104/386b634b9aca4679881e6341dccc8f05.PNG" /> B: f(x)=1 C: f(x)= -1 D: <img src="https://image.zhihuishu.com/zhs/teacherExam_h5/COMMONUEDITOR/202104/8b275b97e5fb4087b7f6018fbcf73ec0.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).

求该电路的极点 [img=153x85]17869e14f5339ec.png[/img] A: 1/(sRC) B: 1/(RC)

电子的自旋磁量子数ms只能取两个值：（） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202006/aad2605165ae49dca6d35f2442486d7d.png"/>，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202006/b26222bd1d104bc48e5b3e46fd0c96f3.png"/> B: 0，1 C: 1，-1 D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202006/53bfe01cafc4489694829394e57b81ab.png"/>，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202006/05ca8a938e7c4b13af4719339d2d12a9.png"/>

通过点<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202009/a13927df1bf542dfa036a32b10364f69.png" />的拉格朗日插值基函数<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202009/65695a42c7a14b649b6aa4fb68f7e499.png" />满足( ) A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202009/99af333f3e934ef6a75022ee1e728b53.png" />＝1，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202009/7769611ac5cd4c93975be7c41a49ae71.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202009/99af333f3e934ef6a75022ee1e728b53.png" />＝1，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202009/7769611ac5cd4c93975be7c41a49ae71.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202009/99af333f3e934ef6a75022ee1e728b53.png" />＝0，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202009/7769611ac5cd4c93975be7c41a49ae71.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202009/99af333f3e934ef6a75022ee1e728b53.png" />=0，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202009/f80e8e400f3f4916bcaf6b5fde757f16.png" />

已知<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/022be9febdbf4485b8e30dd813a50286.png" />溶液的氢离子浓度是<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/1c86b20811cc4194b4da92dd5ae66240.png" />溶液的氢离子的浓度的（ ）。 A: 1/8 B: 1/4 C: 1/2 D: 1/6

要使<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/c4b80714c3b14a559ae5bdcd09ef1fc6.png"/>是线性方程组AX=0的基础解系，则只要系数矩阵A=（ ）. A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/fb16cbefa5a746599e585bcf30dce878.png"/> B: ［2 1 1］ C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/df5d7a834bd44f44a519eaffffd47d39.png"/> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/5adacc7663b444d69f148ab2e7a11cf1.png"/>

若x2+y2=1，则dy为（ ） A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201905/d045b5f235a54083ab91e6f717cf00d8.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201905/74173c5355234874ab8cb9275865d5d6.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201905/bbfb37ba58fc4de0aa8688e0bb53cef5.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201905/f9a206c25e8c4ea1bd7b51519afd76b7.png" />