fX(x)=∫[-∞,∞] p(x,y)dy=(sinx)/2fY(y)=∫[-∞,∞] p(x,y)dx=(siny)/2p(x,y)=fX(x)fY(y)x,y独立,且同分布.因为独立,所以ρ(xy)=0E(A)=∫∫[-∞,∞] xyp(x,y)dxdy=π/4同分布.E(X)=E(Y)=∫[-∞,∞] xf(x)dx=π/4E(...