设x1]-|||-X= x2 =[ (y)_(1),(y)_(2),... ,(y)_(n)] -|||-xn，请问YX=XY，正确吗？对错

(9)设 f(x)= ) (x)^2+2x-3, xleqslant 1 x, 1lt xlt 2 2x-2, xgeqslant 2f(x)=-|||-__

1.用洛必达法则求下列各极限:-|||-(1) lim _(xarrow 0)dfrac (ln (1+x))(x)-|||-(3) lim _(xarrow a)dfrac (cos x-cos a)(x-a);-|||-(5) lim _(xarrow dfrac {pi )(2)}dfrac (ln sin x)({(pi -2x))^2};-|||-(7) lim _(xarrow 0)+dfrac (ln tan 3x)(ln tan 4x);-|||-(9) lim _(xarrow +infty )dfrac (ln (1+dfrac {2)(x))}(arctan x)-|||-(11)lim xcot 3x;-|||-(13) lim _(xarrow 1)(dfrac (2)({x)^2-1}-dfrac (1)(x-1))-|||-1515) limx^(100°;;-|||-(2) lim _(xarrow 0)dfrac ({e)^x-(e)^-x}(sin x)-|||-(4) lim _(xarrow 0)dfrac (sin ax)(tan bx)(bneq 0)-|||-(6) lim _(xarrow a)dfrac ({x)^5-(a)^5}({x)^3-(a)^3}-|||-(8) lim _(xarrow dfrac {pi )(2)}dfrac (tan x)(tan 5x);-|||-(10) lim _(xarrow 0)dfrac (ln (1+{x)^2)}(sec x-cos x)-|||-(12) lim _(xarrow 0)(x)^2(e)^dfrac (1{{x)^2}} =-|||-(14) lim _(xarrow infty )((1+dfrac {3)(x))}^x =-|||-(16) lim _(xarrow 0+{(dfrac {1)(x))}^sin x}

求指导本题解题过程，谢谢您！2.(10分)已知连续型随机变量X的概率密度为 f(x)= ) Ax+B,1leqslant xleqslant 3 0, . 且知-|||-X在区间(2,3)内取值的概率是在区间(1,2)内取值的概率的二倍,试确定常数A,B.

[题目]关于函数: =x-ln x 的极值正确结论-|||-是 ()-|||-A,有极小值1,-|||-B,有极大值1,-|||-C,有极大值 -1,-|||-D,有极小值 e-1

3、设函数 f(x)= { ^-x,xgt 0 x, xleqslant 0 . 则f(x)在 x=0 处 ()-|||-(A)可导 (B)右导数存在而左导数不存在-|||-(C)左导数存在而右导数不存在 (D)连续但不可导

3个方程4个未知量的非齐次线性方程组AX=B，若R(A) =R(A，B) =3，则该方程组一定有（）解。A、唯一B、无穷C、无解D、无法确定

设随机变量X的密度函数varphi(x)是连续的偶函数(即varphi(x)=varphi(-x)),而F(x)是X的分布函数,则对任意实数a有()。A. F(a)=F(-a)B. F(-a)=1-int_(0)^avarphi(x)dxC. F(-a)=(1)/(2)-int_(0)^avarphi(x)dxD. F(-a)=F(a)

离散型随机变量X的概率分布或分布函数也称概率函数是指（）A. X={x)_(2)} =(p)_(i),i=1,2B. X={x)_(2)} =(p)_(i),i=1,2C. X={x)_(2)} =(p)_(i),i=1,2x_i}=p_i,i=1,2,dots" data-width="259" data-height="26" data-size="3063" data-format="png" style="max-width:100%">D. X={x)_(2)} =(p)_(i),i=1,2

17.问λ,μ为何值时，下列线性方程组无解？有唯一解？有无穷多解？当有无穷多解时，求出其通解。}x_(1)+2x_(2)-2x_(3)+x_(4)=1;-x_(2)+x_(3)-x_(4)=0;2x_(1)+x_(2)-x_(4)=3;x_(1)+x_(2)+lambda x_(4)=2-mu.

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