# Joint density function

1. Nov 23, 2009

### mlarson9000

1. The problem statement, all variables and given/known data
Let X and Y be independent uniform (0,1) random variables.

a. find th ejoint density of U=X, V=X+Y.

b. compute the density funciton of V.

2. Relevant equations

3. The attempt at a solution

Part a. is not a problem. I don't understand how the bounds for part b. are set up. The book says: for 0<V<1, fv(v)=$$\int_{o}^{v}$$du
and for 1$$\leq$$v$$\leq$$ 2: $$\int_{v-1}^{1}$$du

Could someone explain this to me?

2. Nov 24, 2009

### mlarson9000

Could somebody explain this in English?