[tex=23.0x1.286]fsN15PQ9VDlQ4nOs6ZIsSOFoAqR77ortHVW3nV7yJ8YSEzkSzSqYJz0hqHg/jOMS/V+L81pL1e/WSS1oAJFgrDsg90r0AiH6fKD+3xHYUO4=[/tex][tex=39.714x1.286]GjX+Dw2WhukG6l9Ju+wFfs5xxoMkZlL326cBM8air6zrsbvUMYQehutg5S0TtyqzKu6boewjIY9IyV+lyjp0i3ptY0rsT6cH68UQS+KrfiA7r2Kw2GJJwAL/cpg7TBhfa0Q55O3nTYE6N34hMsQRFt/64kRs/DdFt9QmqSS3LLOBsSwXlvvSjwyDXyeLUUEp[/tex]

下列选项为某变速器一、二、三、四挡的传动比，则三挡的传动比为（）。 A: 0.969 B: 1.286 C: 1.944 D: 3.455

[tex=39.714x1.286]c/SwrgQvr1J+o87G46mCfdUHzPV6KRWH+8gmBOPijlRUDHk8+qQ0oajQXANkxWEe6YO6jIVLRAZnr9WN5M3MgDbQbg7O1mfn75vcfyh3jejCEgRQ1zWau8+t7zSrAZrw9XMTss8WXHOtNmpVerK7InDsYRDMh+KA89pytkr9UEvGraP8sm4PDrkoKc/rXIWm[/tex][tex=41.857x1.286]HKb0YLFhloxMx3J3FESRG3WFpRgEFW/h61yecPlB1Y7WMh1wAKEtgSXw4TZHDTzNcnW//SFPn3rB6mFixMbzRr3SFtHbi33GER7uAsCwiHjEi0NSoK2Ks7/EOY/HXRY8/3YBJPrS03N582daCL9dN8/R5yco9hyUAjOvDaTzSpX0c6uRN59jjviP+mcvNM8H[/tex][tex=40.286x1.286]qrB6DDVfI+K8aqAwYlmUHenS89DqasmDWQcTC3+JChAtpRuKnDAah61JQQFYbWN7gJ7OdQeLu8gQzr5FEqNw9qLwjGxzalrPof/vPUvJLjX/GvyEBWHZllHwuwB9x3QjY9pl0OkYqdiiVIBW0XfSg2E7wpB5gs7p4syJ/2ndFXv28Hn61XsqUKCkJO4BcnoM[/tex][tex=20.714x1.286]BPx1lUwlmDwMsS9TBuQ11b52KqF9tB4BAU3KCv/qYDmviMJzfye1/WcvgXOEqERX2HUAz1/ct1pfu6S/pa6LJhadbh9LF6VMra3eZT/1A4k=[/tex][img=153x192]179d050f20ff724.png[/img]

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))