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" >

为求方程<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/ce3ea4db5573483a89d1d732d75e1036.png" >在<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/31ea0f26a7064e83856e0c3a268aa9c5.png" >附近的根，则使得迭代格式<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/2cb16d8f43544cca8adc73fc7dce0dff.png" >一定局部收敛的迭代函数为() A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/c52ae5e1d8ca4c51ac71ad740e0bb231.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/54a5d832d2544db7905c50c2c7287f09.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/cdecd203bf8049c5b3faccb7e68a42aa.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/4a5e9a33f10e4d489df882c59db1d545.png" >

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" >

下列表达式正确的是（） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/8c6704bb98b243b2a073149003ccd14d.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/538f492f0c844dfd95e11418fb2301fd.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/f03bb7b7f982489bb62780052c90f61c.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/0698ff5878ce447c801f7a69c87382b8.png" >

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" >