设随机变量(X,Y)的联合密度函数为f(x,y)={21/4x^2y,x^2

问题：设随机变量(X,Y)的联合密度函数为f(x,y)={21/4x^2y,x^2

答案：↓↓↓

傅维暲的回答：

网友采纳　　fx(x)=∫x²~121/(4x²y)dy=(21/4x²)ln(y)|(y:x²~1)=(21/4x²)(-lnx²)fy|x(y|x)=f(x,y)/fx(x)=(1/y)/(-lnx²)=-1/(ylnx²)x=1/2时,密度函数=-1/(yln(1/4...