Have $(U,V)$ be a pair of Bivariate Gaussian variables with mean $0$, variance $1$ and $Cov(U,V) = ρ$ where $0 < ρ < 1$
I'd like help finding the density of $U+V$
So far I have tried to use $P(U+V<=t) = E(P(U+V<=t | V))$ but a am not having much success in advancing. Any help would be appreciated.
Note: This is not a homework problem, but a problem I am doing to help study.