题目
概率数学题设二维随机变量(XY)的联合密度函数
设二维随机变量(XY)的联合密度函数为p(x,y)={k 0
设二维随机变量(XY)的联合密度函数为p(x,y)={k 0
提问时间:2021-01-14
答案
∫ [0,1] {∫ [x^2,x] kdy} dx
= k∫ [0,1] {(1/2)x^2|[上限x,下限x^2]} dx
= ∫ [0,1] (x-x^2)dx
= k (1/2 – 1/3) = k/6 = 1 -- 》k=6
f(x) = ∫[x^2,x] 6 dy = 6(x-x^2), 0
P(X>(1/2)) = 1- P(X<(1/2)) = 1-∫ [0,(1/2)]6(x-x^2) = 1/2
= k∫ [0,1] {(1/2)x^2|[上限x,下限x^2]} dx
= ∫ [0,1] (x-x^2)dx
= k (1/2 – 1/3) = k/6 = 1 -- 》k=6
f(x) = ∫[x^2,x] 6 dy = 6(x-x^2), 0
P(X>(1/2)) = 1- P(X<(1/2)) = 1-∫ [0,(1/2)]6(x-x^2) = 1/2
举一反三
已知函数f(x)=x,g(x)=alnx,a∈R.若曲线y=f(x)与曲线y=g(x)相交,且在交点处有相同的切线,求a的值和该切线方程.
我想写一篇关于奥巴马的演讲的文章,写哪一篇好呢?为什么好
奥巴马演讲不用看稿子.为什么中国领导演讲要看?
想找英语初三上学期的首字母填空练习……
英语翻译
最新试题
- 1莫泊桑短篇小说精选读后感,500~300字
- 2machines; that; for; in; example; error; either; times; which; electronic; mechanical; or; through;
- 3abc为非零有理数a的绝对值分之a加b的绝对值分之b加c的绝对值分之c加ab的绝对分之a
- 4一个数增加他的5分之一后是60,求这个数.(用方程解)
- 5foreign.languages,she did any,learn(?)
- 6在炎热的夏天,呆在凉爽的水里真的太棒了.(it iS fantastiC to),用上括
- 7高二数学,数学高手请进
- 8有序无序的参与政治生活我们青少年该怎样做
- 9I would like a small orange juice用green tea改为选择疑问句
- 10已知六次多项式-5x2ym+1+xy2-6,单项式22x2ny5-m的次数也是6,求m,n的值.
热门考点