设随机变量UND的概率密度函-|||-(x)= dfrac {2)(pi )(sin )^2x,-dfrac (pi )(2)leqslant xleqslant dfrac (pi )(2) .-|||-计算E(X,L{X)

设随机变量X的概率密度为(x)=dfrac (1)(2sqrt {pi )}(e)^-dfrac ({(x-3)^2)(4)}((x)=dfrac (1)(2s

设随机变量X的概率密度为_(x)(x)=dfrac (1)(pi (1+{x)^2)},则Y=2X的概率密度为______ A._(x)(x)=dfrac (1

(sin x)=dfrac (1)({cos )^2x} in (0,dfrac (pi )(2)),则(sin x)=dfrac (1)({cos )^2x}

1.设随机向量(X,Y)的分布函数在 leqslant xleqslant dfrac (pi )(2) leqslant yleqslant dfrac (p

某随机变量 X 的概率密度函数为(x)=dfrac (2)(pi )dfrac (1)({e)^x+(e)^-x}，则分布函数为(x)=dfrac (2)(pi

计算 lim _(xarrow dfrac {pi )(2)}dfrac (ln sin x)({(pi -2x))^2}

求lim _(xarrow dfrac {pi )(2)}dfrac (ln sin x)({(pi -2x))^2}求

2.求下列函数的极值:-|||-(6) (x)=sin x+cos x(-dfrac (pi )(2)leqslant xleqslant dfrac (pi

( (int )_(dfrac {pi )(4)}^dfrac (pi {3)}dfrac (x)({sin )^2x}dx ;

设=(int )_(-dfrac {pi )(2)}^dfrac (pi {2)}dfrac (sin x)(1+{x)^2}(cos )^4xdx, =(in