一维弦振动方程的显式差分格式当
时是稳定的。https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/d48d2e48db0d43f3895860dbd33f3abf.png
时是稳定的。https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/d48d2e48db0d43f3895860dbd33f3abf.png
举一反三
- 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" />
- 下列谓词公式中，是逻辑有效式的是（ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/fd0bc7b26c6e4d91a8ed04b00fa26874.png"> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/42b2e82315144952b187beceb9f746e3.png"> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/efd3b37c91244207886d59b1bd2fdb1e.png"> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/e91d4c4332bb4e12a6e417031fb605fe.png">
- 555定时器构成的施密特触发器其回差电压为（ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/d294eb4b432548a48504d9d90e7d9be1.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/5da5ab9f1aa448519864e9c269244153.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/b2aa7cf60c8142f9acb764a30efcca0e.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/e4b54bf6bf5c4dfa9dc23bb09f1af715.png" />
- 下列各种离子能在酸性溶液中稳定存在的是： A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/8e8cd81b5e664914ba001fe5504ef3d3.png"/> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/5e233a026525441b8ede018e6b5ef10e.png"/> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/3326201131564646aaf802a50d6a5788.png"/> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/4812f416fbc14f74b8bc958a72454138.png"/>
- 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" />