下列表达式正确的是（）
A:
B:
C:
D:
A:
B:
C:
D:
举一反三
- 下列各表达式不正确的是：（） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/3a28e3d5f36c4ef7819646bce49b8edf.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/1a6627e1deba4bd1a1b4b3b05a197bbc.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/98ab6999f98249bbbc3603d54db09a2d.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/dc1e9a6919a54bcaa28e1f8b876967de.png" >
- <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/f9d435b7e7604d1894a0359bb77eb2cc.png" >可写成以下正确的的表达式是（） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/e68f9f4bb1b640068bd1c9e988b3feca.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/1b379e5c6cd74b5da61e39e4ca32ad22.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/44f6ba8e2d6448f4bec35063ad0f689f.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/e25be7e84d1e4f358bb44dacefafd393.png" >
- 理想低通滤波器的传输函数<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/980b5b2a8d7044b697bc516003ea3acb.png" >是()。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/9a82e2e4ff27470da538512097ee6438.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/c079877bd52d471db3cd6e163f62adbb.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/52aa9898f12641d797c40e4d118bd733.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/a7815d7407f34172aeef470a6adc5f47.png" >
- 单边拉普拉斯变换<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/423a53f9b3bf40989454133dbce2d262.png" >的原函数等于（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/301dd2111ac64b0e8217cba94ba1a1ab.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/9772eee6eab34c208eba55009d00041b.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/42bfb5f864e34b5ca02a2a1cc9d9c71b.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/659eef6ba24b490191772fe51bab3c9a.png" >
- 下列Z变换正确为（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/8cfe627e0fb740168b114ff72f3c2ecb.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/a404460444d040dd920cc3ce0a62d29d.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/d158b2dd2dd14823a399a5680f13d9c3.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/9e44b4e907fd4a76902dd04d6284e6b6.png" >