证明在格中成立[tex=12.286x1.357]eM7HfHwIRPcxw515nIok5o/fBSbMYhy3/6uIb0+wA+6+rAmdoPl8ChpC17YjWVqvAheUILeLoa9t5Agse9vvjigSPUFeKCEp8MrAaUpES9o=[/tex]和[tex=18.929x1.357]eM7HfHwIRPcxw515nIok5lkp4X5momZoeoiTUFMd65fme14tNiq1Gqym+3oMbvMlbjYjFjPsyoamdr+k9497Nz+NFsFkqwz+suyDuBNY8A+J6XW4V0wo/nuI8ZFCwAJDKClcwapPTOhDF+c5rVaZL0iARVbwgUdRPKvMuPnpnEQ=[/tex]

求下列齐次差分方程所示系统的零输入响应。[tex=18.929x1.357]qVXezHvNospgVmjfnuVtdgd5yQpet8eEGoxZt/F1Fj1hmyf4SyBU49grP5fBXBPr[/tex]

求下列点集 [tex=0.786x1.0]I/kNMtd8YcgkWCrgriW/hA==[/tex] 的导集[tex=1.071x1.143]/kl5SQf6O9fsMGHhcDhR+g==[/tex]：[tex=18.929x1.357]LyHx0oq/4G26eOfHxWNMgjjET2+UX8pnj48agx3BdICaqAcjrLgIFW9aHw7ea7EBV8HdOqYJi1JRHOQTOLTx/Ul18Ar8XKnULv9Kq8VROOZ0NIgvAIeDF5Z2/73nHxDktXppSApnh+ud2gb2MN4rFQ==[/tex].

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)

判断下列推证是否正确。 (∀x)(A(x)→B(x))⇔(∀x)(￢A(x)∨B(x)) ⇔(∀x)￢( A(x)∧￢B(x) ) ⇔￢(∃x) ( A(x)∧￢B(x) ) ⇔￢( (∃x)A(x)∧(∃x)￢B(x) ) ⇔￢(∃x)A(x)∨￢(∃x)￢B(x) ⇔￢(∃x)A(x)∨(∀x)B(x) ⇔(∃x)A(x)→(∀x)B(x)

以下谓词公式中，( )不是逻辑有效式。 A: ($x)(P(x)∧Q(x)) Þ ($x) P(x)∧($x) Q(x) B: ("x)(P(x)∧Q(x)) Þ ("x) P(x)∧("x) Q(x) C: ($x)(P(x)∧Q(x)) Û ($x) P(x)∧($x) Q(x) D: ("x)(P(x)∧Q(x)) Û ("x) P(x)∧("x) Q(x)

以下谓词公式中，( )不是逻辑有效式。 A: ($x) P(x)∨($x) Q(x) Þ ($x)(P(x)∨Q(x)) B: ("x) P(x)∨("x) Q(x) Þ ("x)(P(x)∨Q(x)) C: ($x) P(x)∨($x) Q(x) Û ($x)(P(x)∨Q(x)) D: ("x) P(x)∨("x) Q(x) Û ("x)(P(x)∨Q(x))