First Moment of Quotient of 2 Random Variables

[schlawalter]

Given three continuos random variables X, Y, Z with well-defined means,
variances, and covariances.  Is it possible to represent E(X/Y) and
E(Z^2/XY) as a function of the means, variances, and covariances of X,
Y, and Z?
Thx in advance,
Christian
e-mail: [EMAIL PROTECTED]