命题“尽管有人聪明，但未必一切人都聪明”的符号化（P(x)：x是聪明的，M(x)：x是人）（）
A:
B:
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D:
A:
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C:
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举一反三
- 已知Z变换Z<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/94487389db974f98b2d38b947ec20d83.png" >，收敛域<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/56b4868c286b4b48a8cec67f9f766670.png" >，则逆变换x（n）为()。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/547656863c8b459da97c366d9321ef13.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/d3572493bf964e2d92fde49d59b632af.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/c4aacba69e0445b0ad4db797b3c86d53.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/b9af7d9dccb3446595a3a587492eb92a.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" >
- 下面命题公式（）不是重言式。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/bad0365bb4ca4e1881dc14640ea47948.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/7ecbabf41ddd44cc8f13850ca398b0a8.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/9119b7a1784e4e8d96a504ca5526afd3.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/7a5be82f20bf418fb65b6946d47061e7.png" >
- 理想不失真传输系统的传输函数H（jω）是()。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/c53311dbea924826a56276a9472741b1.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/4f089e5988004320950aab7179fb9c28.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/2245b8eb25204e8e966be03821487380.png" >（<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/14618be7a9474fa09351a25e922eb774.png" >为常数） D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/9cba3ab48faa4d8980c79f62bb1f3da4.png" ><img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/64f67bce595243aaa13ded6089b431b1.png" >