1.[单选题]-|||-立方晶系中某原胞的基矢 overline ({a)_(1)}=dfrac (a)(2)overline (i) 。 overline ({a)_(2)}=aoverline (x) 》-|||-.overrightarrow ({a)_(3)}=dfrac (a)(2)(overrightarrow (i)-overrightarrow (j)+overrightarrow (k)) ,以其为基矢组成晶体的结构为-|||-bigcirc A.简单立方-|||-bigcirc B.体心立方-|||-bigcirc C.面心立方-|||-bigcirc D.钙钛矿结构

标出具有下列密勒指数的晶面和晶向: ① 立方晶系 (421), (overline(1)23), (130), [2overline(1)1], [311];

作图表示出立方晶系 (123)、(0overline(1)2)、(421) 等晶面和 [overline(1)02]、[overline(2)11]、[346]

.-(x)^2(n) 的简单随机样本, overline (X)=dfrac (1)(n)sum _(i=1)^n(X)_(i) ,则-|||-|E(overl

55单选题设 _(xy)=sum _(xarrow {y)_(4)}((x)_(i)-overline (x))((y)_(i)-overline (y)) ,

(5)设 (A)=dfrac (1)(3), (B)=dfrac (1)(4), (Acup B)=dfrac (1)(2), 则 (overline (A)c

(B) (n-1)(S)^2+(overline {X)}^2 (C) (S)^2+(overline {X)}^2. (D) dfrac (n-1)(n)(S

在立方晶系晶胞中画出下列晶面指数和晶向指数:(001)与[ 2overline (1)0] (111)与[ 2overline (1)0

1.已知 P(A)=1/2 , P(B)=1/3 , (AB)=1/10, 则 (overline (A)cap overline (B))= __

2f=overline(x)_(1)x_(1)+3overline(x)_(1)x_(3)+4overline(x)_(2)x_(2)-3overline(x)

随机事件 A,B 满足 (A)=P(B)=dfrac (1)(2), 且 (Acup B)=1, 则 (overline (A)cup overline (B)