举一反三
- 周期信号f(t)如下图所示，其直流分量为http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/bb02e5afe3fa474093913374442813ab.png
- 已知信号f(t)的波形如下图所示，则f(6-2t)的波形图为http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/414e4bc7b0b44f6e8f660e9dd1189014.bmp
- 下图所示序列f(k)闭合表示式为http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/e3088842d7014311aa5241014415b8f3.bmp
- 信号f1(t)和f2(t)如下图所示，f(t)=f1(t)*f2(t)，则f(-1)等于http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/0749958f4da44655959aea343dbe4d9c.bmp
- 下列尺寸标注正确的是（ ） A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/79ed6f04ee2f415c917c9f280eccf07e.png"> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/4677ac7155c849bebe9d2ffd7458f4c4.png"> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/489ad68ff6294831bc43fa08990b59b7.png"> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/e829c514224942f1926c1823be08d3e7.png">
内容
- 0
如主视图所示，三棱锥被截切，俯视图和左视图正确的是（ ）。 A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/f6dde245be3a4ac286b637f07e1484fc.png"> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/04ae2221fc904cc1ac1caca4daaa8ab1.png"> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/e451d56ab1524240b603f2fa47aad33b.png"> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/0550413aeb5b436c88589bf8de2029af.png">
- 1
下列微分方程中常微分方程的是( ) A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/c24b125c0b534b7696bf33f1e7b98c4c.png"> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/2c9f694c97e9426596d13bed4bd474da.png"> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/7ee1366ebe7a40aa868a143ba15c6ed0.png"> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/d46e4fa33ea0443a938c267c2f07c6b4.png">
- 2
在下图中，螺纹连接画法正确的是（ ）。 A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/388e6231e1fb4ef09858a435d5076944.jpg" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/5c2ff529f94044ffaf8ccbc591499df6.jpg" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/578fcb9927c044a4b982bf3e7e7616a3.jpg" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/bb9122c2834242f4afba03761d066fb8.jpg" />
- 3
下列各表达式中错误的是__ A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/dd20f9d2c1984b1f95ffd89fdf3fed61.png"> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/a7138f62245042a4a604eee2ce27ae93.png"> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/53b05040965a40629cf24d6c90bc7e27.png"> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/8bbfc40de0d6420aa10e572ce4a7b5dd.png">
- 4
下列配合物属于螯合物的是（ ） A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/8f51868d3100497c9f78fe09ba550e3f.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/025b639d0fe9456997a0191bdeb0019a.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/154fd181ff4d421d96ab4d50e3052020.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201906/fbd3f97989994e40a247c9ea17663bd0.png" />