[tex=34.571x1.286]7xa+wlE5JjAt46HQeEfGPFxpyxlztj/3aSDbUv5qfMDVLl+TtQWQO7RpUJbd+1z2c5wGI+Htsq1drW+GRwGFXW8ukpQJDAIKYrwdKhn9Bq7UxA7CC1A848d7T57qc2i5K3n7hZ2TEGQFb+wWT2n0q18gUJU195o/TKTq4hcYPDg=[/tex]

[tex=13.643x1.286]zvd994GpUthv9SiWr7tJngC+irRu0E0tZO6uLkiSAXAIpbxVSuroCorTC+cLNyrvleuCRz6/hNZ6OO/iEm4MJA==[/tex][tex=34.071x1.286]Q9QgTAkZU9OIrwGvSp1njdjSX2xEd+qN8MZuZmNYpTtYZOhfL5Re6ImLZPi0TdeaDJ3oyuF/hItp3e4/WVIQBeyDcD3wmwecuPa14Z7XkRv54UrAF4HT6fAW8tkEUQ/e3iocIu5kSg1bLg0oCZIFsg==[/tex][tex=34.571x1.286]9pMyycabfUapbIBTn3L1EnOL9WSUxrcF8akwlEh+QbEQobR/T0U7G8HFwrcd5xWhXjJBFw2y1MLRPT3ZUwJeyXbOm2LyBNFzhA5C01wFyV1JyHTt1tDuNTB90JLYpA34XP5F/7hcxUg2VOfh8CJ5hg==[/tex]

[tex=13.643x1.286]zvd994GpUthv9SiWr7tJngC+irRu0E0tZO6uLkiSAXAIpbxVSuroCorTC+cLNyrvleuCRz6/hNZ6OO/iEm4MJA==[/tex][tex=34.071x1.286]Q9QgTAkZU9OIrwGvSp1njdjSX2xEd+qN8MZuZmNYpTtYZOhfL5Re6ImLZPi0TdeaDJ3oyuF/hItp3e4/WVIQBeyDcD3wmwecuPa14Z7XkRv54UrAF4HT6fAW8tkEUQ/e3iocIu5kSg1bLg0oCZIFsg==[/tex][tex=34.571x1.286]9pMyycabfUapbIBTn3L1EnOL9WSUxrcF8akwlEh+QbEQobR/T0U7G8HFwrcd5xWhXjJBFw2y1MLRPT3ZUwJeyXbOm2LyBNFzhA5C01wFyV1JyHTt1tDuNTB90JLYpA34XP5F/7hcxUg2VOfh8CJ5hg==[/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

设计一块光栅, 要求 [tex=34.571x1.286]Pueds0K2KLsZW5wurc+R17HO1xH7fvl9bUsrxdyLkReGW4goaFkcZtQeWG8D+T4fiQnI2JOKJVLjcO/n+rNvJRS2u5IfGECmrCspT9jgFBiMz69FmQxQ1W5xr4r56snu5gpOBdtZsC8WAoqaDCxliKRlLkPG6eONwqamqzApXII=[/tex](2)色散尽可能大; (3)第三级谱线缺级。求出其缝宽、缝数、光栅常量和总宽度。用这块光栅总共能看到[tex=3.0x1.0]KFsbEBMYC7JeW7w1XsiuEQ==[/tex]的几条谱线?

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)