满足()A: ≥1
B: =2
C: =0
D: ≤1
举一反三
- 在用高斯消去法解线性方程组AX=b时，消元过程中需满足（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/1ecfbcae4992431ea8b791ff4b149443.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/4eb2a998d5d64712a28c3b92a889dacc.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/5d4a5f3489c14cd781a9b3c4d28e4f3d.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/95d9e5bf118144519ea7d8738ce7348f.png" />
- <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202106/5d5e445f772b4d8e90f7140053f2c0c6.png" />3、用全主元高斯消去法解方程组第一步所选的主元是（ ）。 A: -1. B: 6； C: 1； D: 2；
- 超静定结构如图所示。AB为刚性杆，Δl1和Δl2分别表示1杆和2杆的伸长量。（1）画出结构的变形图；（2）结构的变形协调方程为（）。<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/1d244f931b4f498387e6b53de221a1a0.png" /> A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/4b064cc8699743d8959964f269679df5.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/016f63e17bcf4b0994832a46bdcd4cf6.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/67848f0944be4264890a220ae646822f.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/31a9888b0b0a431c96d0253ea32b18a6.png" />
- 空气与介质<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/1e6362735d6d4ae5a77aaafe5b5b49c7.png" />的分界面为z=0的平面，已知空气中的电场强度为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/f8c5f3e89f4d4570a92c23bb118869fb.png" />,则介质中的电场强度<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/f7bb30061e904b39a8d53ad541435c18.png" />：() A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/c1f29b60a07d4d75aa0f7e1c63a75a2f.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/74f128e456384ac79b8204c33052cbcc.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/c87cbdc5e75c40b4b875455ed5bccd28.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/b1117f3f152d413b89e5c221153014a8.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" >
内容
- 0
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" >
- 1
计算固体试样采集的最小质量的公式为（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/5445c6cd693246e88c1a904c099b5060.png"/> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/00d46949ff1843e6a285343dd85a3d5b.png"/> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/96c678c6ddff4eca8202640c9eea3058.png"/> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/b456b2df98284694872aa226a3b27f55.png"/>
- 2
下列系统中线性时不变系统是（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/4b45f35cbb8b49eea328e0f1af3a3101.png" >（<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/3f1f37fe4ba54c4fb69d1be115a88f2d.png" >为常数） B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/481b4d4b98e24b94a2eaa9ec011e0186.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/f0f925fadec648b4b7c35161be6f3a3d.png" >（<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/c10b602726304747bf5fe38a760da1ae.png" >为常数） D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/62c5dee47e9045cca90a53856dc04845.png" >
- 3
<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" >
- 4
假定<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/71458e4f29a24928a4ad4d36e72ec6b9.png" >，以下关于z变换的性质描述，正确的是：（） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/545e8d644963417494a94eec7ae1bf50.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/04445d84fa3443968231a11a580079e2.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/5599b26833e546dfa3ab9c1c656c6581.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/fcc7d5135a714189b801863712e6b7f5.png" >