# Random variables Question

• Jan 7th 2010, 07:48 PM
thanapa
Random variables Question
For random variables X,Y and Z it is given that

$Cov(X,Y) = \alpha$ and $Cov(X,Z) = \beta$

Obtain $Cov(X,Y+Z)$
• Jan 7th 2010, 10:53 PM
matheagle
$Cov(X,Y) = \alpha$ and $Cov(X,Z) = \beta$
Obtain $Cov(X,Y+Z)=Cov(X,Y)+Cov(X,Z)=\alpha+\beta$