求[tex=4.071x2.429]ENxIatiC2yqgaopSQCG83gc6sHJMVToraJOquV9v2Rbg1ugnmXTlarjvcg2f8iE9[/tex]

判断数列是收敛，还是发散？对于收敛数列，通过观察数列[tex=2.0x1.357]h3eICLkAlY54v5UBwjQ4sBI1zHM9ZDqJprUj0GNfH3U=[/tex]的变化趋势，写出它们的极限[tex=4.071x2.429]mBCZQMW/5LjRNwAQZYRVR5iAKFzpZ1HscYN6r8dR5rE=[/tex]

下列极限存在的是 未知类型：{'options': ['[tex=5.429x2.5]ENxIatiC2yqgaopSQCG83mnuGMqJb0xELb37sIo0Z2pvaMcfXQmQb4gfsJ9Jt0X2FzMhe0EheYzvECmPZ7Yf5w==[/tex]', '[tex=4.071x2.429]ENxIatiC2yqgaopSQCG83o6+oJRvD5QCnaUESzTMPB1ZpX+/aEHzwo5akb4x8Fq1[/tex]', '[tex=6.071x2.786]ENxIatiC2yqgaopSQCG83jfDTyyYEXSi2WH/phGcwgvQXCfLF+n4rHWD1IIw8cSbAn+uPBCuBT7NSkH0wGQRxw==[/tex]', '[tex=3.071x2.429]ENxIatiC2yqgaopSQCG83voPQUyjx/mPfRkFwsrnXIH+sGraGzWrv+xuwlkFzfwg58Bd7MKlA0Zz7YAs+WxmkQ==[/tex]'], 'type': 102}

已知单位反馈系统的开环传递函数及其幅相曲线如下,试根据奈氏判据判断闭环系统的稳定性。[br][/br][tex=4.071x2.429]IjGjv0jgLoGFumGDFgOLB1o4TkeThsqkiV9hyTEBoCM=[/tex][img=138x142]17a5fab649df7b1.png[/img]

下列数列是收敛的还是发散的? 如果是收敛数列，通过观察得出数列的极限, 并试着用数列的极限定义证明得到的结果.[tex=4.071x2.429]xYO+T6Jo7n65JASnrSXfxddE/6XA9T+dEINiiYmXXDQ=[/tex]

下列极限存在的是[input=type:blank,size:4][/input]. 未知类型：{'options': ['[tex=5.429x2.429]ENxIatiC2yqgaopSQCG83mnuGMqJb0xELb37sIo0Z2pbRDB0ximP5hX64UD3CILBoeZvDrD1Si9W60wVo5UM9w==[/tex]', '[tex=4.071x2.429]ENxIatiC2yqgaopSQCG83o6+oJRvD5QCnaUESzTMPB1ZpX+/aEHzwo5akb4x8Fq1[/tex]', '[tex=2.571x2.143]MhC0sa4kP8ihnFHLNuEHS12331GvaEYwG1PVrQ41JNr1/orm12iixvuqsP0FIiiqM8Od7Zv+w1wsdB5cPA88vg==[/tex]', '[tex=5.929x2.786]ENxIatiC2yqgaopSQCG83jfDTyyYEXSi2WH/phGcwgvQXCfLF+n4rHWD1IIw8cSb0cHF4TUIhOIqp70yjxAkog==[/tex]'], 'type': 102}

下列变量组（）是一个闭回路。 A: {x，x，x，x，x，x} B: {x，x，x，x，x} C: {x，x，x，x，x，x} D: {x，x，x，x，x，x}

以下谓词蕴含式正确的是（）: (∀x) (A(x)→B(x))=>( ∀x)A(x)→(∀x)B(x)|(∀x) (A(x)↔B(x))=>( ∀x)A(x)↔(∀x)B(x)|(∀x)A(x)∨(∀x)B(x)=>( ∀x) (A(x)∨B(x))|(∃x) (A(x)∧B(x))=>(∃x)A(x)∧(∃x)B(x)

以下谓词蕴含式正确的是（）: (?x) (A(x)→B(x))=>( ?x)A(x)→(?x)B(x)|(?x) (A(x)?B(x))=>( ?x)A(x)?(?x)B(x)|(?x)A(x)∨(?x)B(x)=>( ?x) (A(x)∨B(x))|(?x) (A(x)∧B(x))=>(?x)A(x)∧(?x)B(x)

下列式中错误的是： A: (∀x)(A(x)Úp(x)) Û (∀x)A(x)Ú (∀x)p(x) B: ($x)A(x) Ù p Û ($x)(A(x) Ù p ) C: (∀x)(A(x)ÚB(x)) Þ (∀x)A(x)Ú( ∀x)B(x) D: ($x)(A(x)ÙB(x)) Þ ($x)A(x)Ù( $x)B(x)