Computing a transformation of a bivariate random variable Given the bivariate random variable (X,Y) with PDF: 
$   \begin{cases} 
   \frac{2}{7}(2x+5y) &amp; 0&lt;x&lt;1,\ 0&lt;y&lt;1 \\
   0 &amp; otherwise 
   \end{cases}
    $


$ Let\ Z=\frac{Y}{X}. Compute\ the\ probability\ density\ function\ of\ Z. $
$Compute \ P(X&gt;\frac{1}{3}|Z=z) for \ z \in(0,\infty) $


I tried computing the Jacobian matrix but am not sure what to do then.
Thanks
Using delta function approach ...

$$p(z')dz' = \delta(z'-z(x,y))p(x,y)dx dy$$

and hence

$$P(z''&lt; z)=\int_0^z{p(z')}dz'$$
Using delta function approach ...

$$p(z')dz' = \delta(z'-z(x,y))p(x,y)dx dy$$

and hence

$$P(z''&lt; z)=\int_0^z{p(z')}dz'$$