The joint density function of X and Y is given by

$\displaystyle f(x, y) = \frac{1}{2\sqrt{2\pi}}\frac{e^{-y/2}}{y^{3/2}}$, where $\displaystyle |x| < y < \infty $.

Find $\displaystyle E[X|Y]$.

How do I go about doing this question? Any help is appreciated. Thanks in advance!(Happy)