Let $\displaystyle U$ denote a random variable uniformly distributed over $\displaystyle (0,1)$. Compute the conditional distribution of $\displaystyle U$ given that

$\displaystyle U>a$

where $\displaystyle 0<a<1$

So if I understand this correctly, we desire

$\displaystyle f_{U|U>a}(U|U>a)=\frac{f(U, U>a)}{f_{U>a}(U>a)}$

How do I proceed from here, assuming I'm correct?