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【判断题】
接1题，当Rb2增大时，
减小，
A.
正确
B.
错误
举报
参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】From the conversation, we know that a cluster diagram always includes _______.
A.
topic sentence, evidences, explanation for each
B.
topic sentence, explanation, conclusion
C.
topic sentence, data analysis, explanation
D.
topic sentence, evidences, conclusion
【单选题】设$f(x) = \left\{ \begin{array}{l} 2{{\rm{e}}^{x - 1}}{\rm{, }}\qquad\quad \;\;x < 2, \\ {\log _3}({x^2} - 1),{\rm{ }}\quad x \ge 2, \\ \end{array} \right. $, 则$f(f(2)) = $( ).
A.
0
B.
1
C.
2
D.
3
【单选题】设随机变量\(X\)的概率密度函数\(\phi(x)=\frac{1}{\pi(1+x^2)}\)，求随机变量\(Y=aX^2,(a < 0)\)的概率密度函数\(f(y)\)
A.
\[ f(y)=\left\{ \begin{aligned} -\frac{1}{\pi(a+y)}\sqrt{\frac{a}{y}} &,& y < 0 \\ 0 &,& y \geq 0 \end{aligned} \right. \]
B.
\[ f(y)=\left\{ \begin{aligned} -\frac{1}{\pi(a+y)}\sqrt{\frac{a}{2y}} &,& y < 0 \\ 0 &,& y \geq 0 \end{aligned} \right. \]
C.
\[ f(y)=\left\{ \begin{aligned} -\frac{1}{\pi(a+y)}\sqrt{\frac{a}{2y}} &,& y > 0 \\ 0 &,& y \leq 0 \end{aligned} \right. \]
D.
以上答案均不正确
【单选题】设离散型随机变量\(X\)的分布函数为\[ F(x)=\left\{ \begin{aligned} 0 &,& x < -1 \\ 0.4 &,& -1 \leq x < 1 \\ 0.8 &,& 1 \leq x < 3\\ 1 &,& x \geq 3 \end{aligne...
A.
\(\frac{1}{3}\)
B.
\(\frac{2}{3}\)
C.
\(\frac{4}{5}\)
D.
以上答案均不正确
【单选题】设$f(x) = \cos x, f(\varphi (x)) = 1 - {x^2}$, 则$\varphi (x) $的定义域是( ).
A.
$(-\infty,+\infty) $
B.
$[-\sqrt{2},\sqrt{2}] $
C.
$[-1,1] $
D.
$[0,{\rm{\pi }}] $
