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=23.786x1.286]HHtzKZndLaPUT8iFpYgpDld197WTimsWlXmFbQSCYtB/LtfNlriW6pR2DMcpdfFB1rC43MwHhXSCEurEG6D1D6UZ+SVUHk7rJiVymhPJu7UHUBclYakX/Y79TBrzvltr[/tex][img=428x251]179d58b2ff9c250.png[/img][tex=19.214x1.286]UcRL/zogqY/VKCY/3fJb4zc/gWFdgM6rqLn1sArw6tA3ZVt5Tvl+EFTpVLAfyb1NZKeoLwuuWlfDyZZoKEBWw8vmsjKQsX60HSnlzlr5oww=[/tex][tex=17.357x1.286]toAaq0b/hE7HKxv7lARHrGCP/S2GueHBjL9SmDVzeAsya9hjqzxqjJ8pOhhQ5wgliFlZ7k95d7XPUm7rcctfYA==[/tex][tex=17.214x1.286]+aY9epAJb5IF3flGhCvgFf+sK7j4w1iYtt/U3ppxwNe4yRLnKFXVQPVUXPk1gYlo5xnvH0v5TKRRsTaVmjP63A==[/tex]

有关热分析的叙述错误的是 未知类型：{'options': ['[tex=17.214x1.286]YwQgIIcyZJ0m7Tvyxxbk5SHAHUYWkKKdtWrL/W3o+DiJjev6GFZ3ffF4MOMbLrCXf4nGFJVSWNtjXQMgTGdAfA==[/tex]', '[tex=16.071x1.286]m2fiYR/XHxzzziwrZ7yt7TKKuYqyezrgECOshZTGPshYI006EfWQEZwFIl3GcRVrGkgkT5p8doLV/+vNUjUYzg==[/tex]', '[tex=20.286x1.286]PFd2ululuRgDdxUWCHzaD1GdrSSY+t+jRPebrxKV0lutJLjAiXx6BX2KTr7a3O2dfnwqoI5RLzDklTFf53ovt3LA3Xe+3Qa27zYuMOBJ7R8=[/tex]', '[tex=14.643x1.286]9xoaznP63Soem+W5KpIZH4b0wEwWb3kREKHD6T0wfyNImxTeDPF6O57G3cpNhadH[/tex]'], 'type': 102}

在实验室中通常用下列反应制取氯气：[tex=17.214x1.286]U1JSEYYNxfalGoqA8u0iBzAF7Gr5AhUNm3gYh1V9gzL1roqALxMms7qNQnKJgKeXAh14BAgECNvtG5OmqlODkw==[/tex]通过计算回答，为什么必须使用浓盐酸？已知[tex=12.214x1.286]m5LhX8fB7NibYhWjzXJSwq7xsdj+xFGqQAWbmAxpC2SRXm62DN/oFb2ciJuiifCAXbDhIR1bQLBJXF8PNidu+w==[/tex]，[tex=10.0x1.286]m5LhX8fB7NibYhWjzXJSwu3P+4jt1bjgzW250rgW/S0P7OW3h2yi0hNLP2MFQjlw50bqhOvVARo+eiIvaZpSOA==[/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)

在汽缸盖上要钻四个相同的孔如图2-2所示，现估计钻每个孔的切削力偶矩[tex=17.214x1.286]LsL7Ws8YWHRqesuoYTq66uHLAOWght+JSf0mrg2zhbnYfv8qWeDhgKL58pY/yCDC[/tex]，当用多轴钻床同时钻这四个孔时，间工件受到的总切削力偶矩是多大？[img=273x193]17d1a2da1c6a252.png[/img]