设 是锥面 被柱面所割下的有限部分，则https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/d6dcdeccf1a646a6be9eb663eabc4ab2.png
举一反三
- 设A=<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/bc546fc03fdb4ba3b7e6b144b6371d7f.png" />，B=Р(Р(A)) 下列（ ）表达式不成立。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/6e615703da60435893f9e9a9273e12e5.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/64c831067d054e71a6c76f43849d450d.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/72023a5250e44c12b98923044194f13d.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/c48e039a739c4502830eee7ae0ac1678.png" />
- 下列方程所对应的曲面为双曲抛物面的是（ ） A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/3d9f8275e809414fb56a08f8128ba5d0.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/08c3e00fc9dd4a8c80260f92cbe9abd8.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/eda72acdb3ae4cf189947af5eefee38d.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/4ef0c2211e5840aea14a76e80e8965a5.png" />
- 设论域为整数集，下列公式中值为真的是（ ） A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/2711e476b621420282b7b5a9e859fa6b.png"> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/170e20f6765346308a85d187b2cb10e9.png"> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/7dde811e51824a06a3e118fe0c07d6fb.png"> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/e2efbc62e6bc46e1b21e083664b89585.png">
- 根据下列反应所设计的原电池，不需用惰性电极的是： A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/13bf819be57e4868ae15422ce93419c2.png"/> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/0f9eae62c38642dd8383812394fad632.png"/> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/932b51b6cec14158a6859ef62e83d636.png"/> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/cd199fef52cc4c1796ab4fb42c475fed.png"/>
- 下列各对物质所组成的溶液，具有缓冲作用的是： A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/7ce02dd733ea47aaaee6ad3ad4f08c53.png"/> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/8c239f1071944b608d70f007d9bfe4c4.png"/> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/e29919c10b844310991376c5572587c1.png"/> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/d5a92b9edc7a4930b92903397e8e8c44.png"/>