2f=overline(x)_(1)x_(1)+3overline(x)_(1)x_(3)+4overline(x)_(2)x_(2)-3overline(x)
[单选题]在F(x)中,次数≤n的多项式h(x)若在F中n+1个根,则h(x)是什么多项式?()A . 一次多项式B . 任意多项式C . 二次多项式D . 0.0
(B) (n-1)(S)^2+(overline {X)}^2 (C) (S)^2+(overline {X)}^2. (D) dfrac (n-1)(n)(S
2.6 证明式(2.42)var(hat(beta)_(0))=[(1)/(n)+((overline(x))^2)/(sum(x_(i)-overline{x
若 z^2 = (overline(z) )^2,则必有()A. $z = 0 $B. $Re z = 0 $C. $Im z = 0 $D. $$ $Re
[问答题]设多项式Pn(x)在x=1处有等于6的极大值,在x=3处有等于2的极小值,则其中次数n最低的多项式Pn(x)=________。
A)(overline(X) - u_(alpha) (2)/(sqrt(n)), overline(X) + u_(alpha) (2)/(sqrt(n))
.-(x)^2(n) 的简单随机样本, overline (X)=dfrac (1)(n)sum _(i=1)^n(X)_(i) ,则-|||-|E(overl
13.-|||-多项式 ((x)_(1),(x)_(2),(x)_(3))=(({x)_(1)+(x)_(2))}^2+(({x)_(1)+(x)_(3))}^
,-|||-则该多项式的根为 () .-|||-(A)0; (B) -1 ; (C) -2 ; (D) -3 _